1. The Madman Theory

The United States has no diplomatic relations with North Korea, so there is no embassy in Washington, but for years the two countries have relied on the “New York channel,” an office inside North Korea’s mission to the United Nations, to handle the unavoidable parts of our nonexistent relationship. The office has, among other things, negotiated the release of prisoners and held informal talks about nuclear tensions. In April, I contacted the New York channel and requested permission to visit Pyongyang, the capital of the Democratic People’s Republic of Korea.

The New York channel consists mostly of two genial middle-aged men: Pak Song Il, a husky diplomat with a gray brush cut; and his aide-de-camp, Kwon Jong Gun, who is younger and thinner. They go everywhere together. (The North Korean government has diplomats work in pairs, to prevent them from defecting, or being recruited as spies.) Under U.S. law, they can travel only twenty-five miles from Columbus Circle. Pak and Kwon met me near their office, for lunch at the Palm Too. They cautioned me that it might take several months to arrange a trip. North Korea periodically admits large groups of American journalists, to witness parades and special occasions, but it is more hesitant when it comes to individual reporters, who require close monitoring and want to talk about the nuclear program.

Americans are accustomed to eruptions of hostility with North Korea, but in the past six months the enmity has reached a level rarely seen since the end of the Korean War, in 1953. The crisis has been hastened by fundamental changes in the leadership on both sides. In the six years since Kim Jong Un assumed power, at the age of twenty-seven, he has tested eighty-four missiles—more than double the number that his father and grandfather tested. Just before Donald Trump took office, in January, he expressed a willingness to wage a “preventive” war in North Korea, a prospect that previous Presidents dismissed because it would risk an enormous loss of life. Trump has said that in his one meeting with Barack Obama, during the transition, Obama predicted that North Korea, more than any other foreign-policy challenge, would test Trump. In private, Trump has told aides, “I will be judged by how I handle this.”

On the Fourth of July, North Korea passed a major threshold: it launched its first intercontinental ballistic missile powerful enough to reach the mainland United States. In response, on July 21st, authorities in Hawaii announced that they would revive a network of Cold War-era sirens, to alert the public in the event of a nuclear strike. Trump said that he hopes to boost spending on missile defense by “many billions of dollars.” On September 3rd, after North Korea tested a nuclear weapon far larger than any it had revealed before—seven times the size of the bombs dropped on Hiroshima and Nagasaki—the U.S. Secretary of Defense, James Mattis, warned that a threat to America or its allies would trigger a “massive military response.”

A few days after the July 4th missile test, Pak told me that I could book a flight to Pyongyang. I submitted a list of people I wanted to interview, including diplomats and Kim Jong Un himself. About the latter, Pak only laughed. (Kim has never given an interview.) After Pak stopped laughing, he said I could talk to other officials. I wanted to understand how North Koreans think about the kind of violence that their country so often threatens. Were the threats serious, or mere posturing? How did they imagine that a war would unfold? Before my arrival in North Korea, I spent time in Washington, Seoul, and Beijing; many people in those places, it turned out, are asking the same things about the United States.

About a week before my flight to Pyongyang, America’s dealings with North Korea deteriorated further. On August 5th, as punishment for the missile test, the U.N. Security Council adopted some of the strongest sanctions against any country in decades, blocking the sale of coal, iron, and other commodities, which represent a third of North Korea’s exports. President Trump, in impromptu remarks at his golf club in New Jersey, said that “any more threats to the United States” will be met “with fire and fury like the world has never seen.” A few hours later, North Korea threatened to fire four missiles into the Pacific Ocean near the American territory of Guam, from which warplanes depart for flights over the Korean Peninsula. Trump replied, in a tweet, that “military solutions are now fully in place, locked and loaded, should North Korea act unwisely.”

Suddenly, the prospect of a nuclear confrontation between the United States and the most hermetic power on the globe had entered a realm of psychological calculation reminiscent of the Cold War, and the two men making the existential strategic decisions were not John F. Kennedy and Nikita Khrushchev but a senescent real-estate mogul and reality-television star and a young third-generation dictator who has never met another head of state. Between them, they had less than seven years of experience in political leadership.

Brinkmanship, according to Thomas Schelling, the Nobel Prize-winning economist who pioneered the theory of nuclear deterrence, is the art of “manipulating the shared risk of war.” In 1966, he envisaged a nuclear standoff as a pair of mountain climbers, tied together, fighting at the edge of a cliff. Each will move ever closer to the edge, so that the other begins to fear that he might slip and take both of them down. It is a matter of creating the right amount of fear without losing control. Schelling wrote, “However rational the adversaries, they may compete to appear the more irrational, impetuous, and stubborn.” But what if the adversaries are irrational, impetuous, and stubborn?

Three days after Trump’s “locked and loaded” tweet, I flew from Beijing to Pyongyang. The flight was mostly empty, except for some Chinese businessmen and Iranian diplomats. I was accompanied by the photographer Max Pinckers and his assistant, Victoria Gonzalez-Figueras. In the air, I deleted from my laptop some books about North Korea; the government is especially sensitive about portrayals of the Kim family. (When you buy a North Korean newspaper with an image of Kim Jong Un on the front page, the clerk folds it carefully, to avoid creasing his face.) The airport was quiet and immaculate. At customs, when I opened my suitcase, I saw that I had forgotten to discard two books: “The Great Successor,” an account of Kim’s ascent, and “The Impossible State.” The customs officer called over a colleague, who flipped through the pages and alerted his superiors. I was led to a room, where an officer told me that the books are “very disparaging about the D.P.R.K.” He wanted to know where and when I had bought them, and whether I had read them. After some discussion, I was told to write a statement promising “never to bring them to the D.P.R.K. again.” I signed it, the books were confiscated, and I hustled on.

I was approached by a smiling man in a crisp white short-sleeved button-down shirt with a small red pin on his left breast, bearing a likeness of Kim Il Sung—Kim Jong Un’s grandfather, and the first leader of North Korea. (Citizens over the age of sixteen are expected to wear a badge celebrating at least one of the Kims.) He introduced himself, in English, as Mr. Pak, of the Foreign Ministry’s Institute for American Studies, and said that he would be my guide. I followed him outside, where the air was clear and still. Pak presented the others who would be accompanying us: two drivers and a slim young man with a military bearing named Mr. Kim, who provided only one-word answers to my occasional queries. Pak and I climbed into a Toyota S.U.V.

Pak—by coincidence, he has the same full name, Pak Song Il, as the senior member of the New York channel—is thirty-five years old, with short bushy hair and a placid demeanor. Most of North Korea’s twenty-five million people are not permitted to travel abroad, but Pak’s job has allowed him to visit several countries, which he described in terms of their cleanliness: Switzerland (very clean); Belgium (not so clean); Bangladesh (not clean at all). In 2015, he went to Utah (clean) for a nongovernmental exchange attended by members of the Church of Jesus Christ of Latter-Day Saints. The experience convinced him that Mormons have a lot in common with North Koreans. “When the L.D.S. started, they were hated,” he told me. “They were sent to the desert. But they made it thrive. They are organized like a bee colony, where everyone works for one purpose and they would die for it. And they make huge output, as a result. We understand each other very well.”

Pak spends most of his time analyzing American politics and news reports, trying to divine America’s intentions regarding North Korea. Since the election of Donald Trump, he said, the task had become more demanding. “When he speaks, I have to figure out what he means, and what his next move will be,” he said. “This is very difficult.”

That would probably please Trump, who prides himself on being unpredictable. Many commentators have drawn comparisons to Richard Nixon and his “madman theory” of diplomacy, in which Nixon sought to leave his adversaries with the impression that he possessed an unstable, dangerous state of mind.

Later, I asked Pak what he and other North Koreans thought of Trump.

“He might be irrational—or too smart. We don’t know,” he said. They suspected that Trump’s comment about “fire and fury” might be part of a subtle strategy. “Like the Chinese ‘Art of War,’ ” he said. “If he’s not driving toward a point, then what is he doing? That is our big question.”

For Pak and other analysts in North Korea, the more important question about the United States extends beyond Trump. “Is the American public ready for war?” he asked. “Does the Congress want a war? Does the American military want a war? Because, if they want a war, then we must prepare for that.”

We arrived at the Kobangsan Guest House, a small, three-story hotel on the outskirts of Pyongyang, surrounded by corn and rice fields. The place had an air of low-cost opulence—chandeliers, rhinestones, and pleather sofas. We were the only guests. The Foreign Ministry uses the hotel for “Americans and V.I.P.s,” Pak said. (In 2013, Eric Schmidt, the former C.E.O. of Google, was put up there.) In North Korea, no visitor is left unattended, and Pak had a room down the hall from mine. I paid a hundred and forty-one dollars a night—a month’s income for the average citizen. “From time immemorial, there is a tradition of giving foreigners the best service,” Pak explained. “The No. 1 thing is to protect them, unless they are spies or enemies.”

We had dinner that night with Ri Yong Pil, a Foreign Ministry official in his mid-fifties, who is the vice-president of the Institute for American Studies. Gregarious and confident, he served eight years in the Army, learned English, and became a diplomat. He raised a glass of Taedonggang beer and toasted our arrival. We were in a private hotel dining room that felt like a surgical theatre: a silent, scrubbed, white-walled room bathed in bright light. Two waitresses in black uniforms served each course: ginkgo soup, black-skin chicken, kimchi, river fish, and vanilla ice cream, along with glasses of beer, red wine, and soju. (The U.N. says that seventy-two per cent of North Koreans rely on government food rations, and the country is experiencing a historic drought. But in Pyongyang a foreign guest eats embarrassingly well.)

Ri made a series of points, waiting for me to write each one in my notebook:

“The United States is not the only country that can wage a preventive war.”

“Three million people have volunteered to join the war if necessary.”

“Historically, Korean people suffered because of weakness. That bitter lesson is kept in our hearts.”

“Strengthening our defensive military capacity is the only way to keep the peace.”

“We are small in terms of people and area, but in terms of dignity we are the most powerful in the world. We will die in order to protect that dignity and sovereignty.”

After several more toasts, Ri loosened his tie and shed his jacket. He had some questions. “In your system, what is the power of the President to launch a war?” he asked. “Does the Congress have the power to decide?”

A President can do a lot without Congress, I said. Ri asked about the nuclear codes: “I’ve heard the black bag is controlled by McMaster. Is it true?” (He was referring to H. R. McMaster, the national-security adviser.)

No, the President can launch nukes largely on his own, I said. “What about in your country?”

His answer was similar. “Our Supreme Leader has absolute power to launch a war,” he said.

I turned in early. My room was furnished in the style of Versailles by way of Atlantic City—champagne-colored leather and gold-painted trim. The room was equipped with a TV, but, instead of North Korean programming, the only options were Asian satellite channels. There was no news to be found. I flipped past a Christian evangelist and a Singaporean cooking show, and drifted off to the sight of sumo wrestlers colliding.

Trump is the fourth U.S. President who has vowed to put an end to North Korea’s nuclear program. Bill Clinton signed a deal in which North Korea agreed to freeze its nuclear development in exchange for oil and a civilian reactor, but neither side fulfilled its commitments. George W. Bush refused bilateral negotiations, then switched tacks and convened what are known as the Six-Party Talks. Obama first offered inducements, and later adopted a stonewalling policy called “strategic patience.” Under Trump, the U.S. has led the U.N. Security Council in its passage of the eighth round of sanctions against North Korea in eleven years. The Kims’ nuclear program is still going. “They have managed to play an abysmally bad hand for more than seventy years,” Evans Revere, a former head of Korean affairs at the State Department, told me.

U.S. intelligence has often underestimated the progress of North Korea’s weapons development. But now the basic facts, accumulated by American, European, and Chinese intelligence agencies, are clear. North Korea has between twenty and sixty usable nuclear warheads, and ICBMs capable of hitting targets as far away, perhaps, as Chicago. It has yet to marry those two programs in a single weapon, but American intelligence agencies estimate that it will achieve that within a year. The U.S. is in the process of upgrading its ability to shoot down an incoming missile. It reportedly tried to derail North Korea’s weapons development through cyber sabotage, but it only delayed the progress. A former U.S. official said, “You spend millions putting it in place and then you ask, ‘Did it work?’ And the answer comes back: Maybe.”

In recent talks, when Americans have asked whether any combination of economic and diplomatic benefits, or security guarantees, could induce Pyongyang to give up nuclear weapons, the answer has been no. North Koreans invariably mention the former Libyan leader Muammar Qaddafi. In 2003, when Qaddafi agreed to surrender his nuclear, chemical, and biological weapons, Bush promised others who might do the same that they would have an “open path to better relations with the United States.” Eight years later, the U.S. and nato helped to overthrow Qaddafi, who was captured, humiliated, and killed by rebels. At the time, North Korea said that Qaddafi’s fall was “a grave lesson” that persuading other nations to give up weapons was “an invasion tactic.”

James Clapper, the former director of National Intelligence, who visited Pyongyang in 2014, told me, “The North Koreans are not going to give up their nuclear weapons. It’s a non-starter.” The American national-security community is now nearly unanimous on this point, but the government cannot say so openly, because that would cede leverage in a future negotiation, and raise the risk that other countries will try to follow North Korea’s example. “Whether it’s pressuring, threatening, negotiating, or trying to leverage China, everybody’s tried all of that—and it’s not working,” Clapper said.

Inside the Trump Administration, there is disagreement about how to handle North Korea. Shortly before Steve Bannon, the President’s former chief strategist, was fired, in August, he told an interviewer, “There’s no military solution here, they got us.” But Mattis and McMaster argue that Kim Jong Un must be contained. Testifying before the House Armed Services Committee in June, Mattis called North Korea “the most urgent and dangerous threat to peace and security,” supplanting Russia as the No. 1 threat to the U.S. In an e-mail, McMaster told me, “Their provocations seem likely to increase—not decrease—over time. The North Koreans have also proliferated just about every capability they’ve ever produced, including chemical weapons and a nuclear reactor. Then there’s the matter of what other countries do—in the region and beyond—when they see that a rogue regime developed nukes and got away with it.”

Experts can’t say definitively why Kim wants nuclear weapons. Are they for self-defense, as North Korea claims, or will Kim use them to achieve the unfulfilled ambition of the Korean War—forcing reunification with South Korea? A senior Administration official told me that members of Trump’s national-security team are not convinced that Kim will stop at self-protection. “There are fewer and fewer disagreements about North Korea’s capabilities now, and so then, inevitably, the question of their intentions becomes critical,” he said. “Are they pursuing these weapons in order to maintain the status quo on the Peninsula, or are they seeking to fundamentally alter the status quo?” The official added, “Sometimes dictators are able to kid themselves that ‘Hey, once I’ve got that weapon, I’m invincible, and I have a free hand to launch conventional wars and subversion and assassination campaigns against my neighbors.’ ”

The White House could try to deter North Korea from using or selling its weapons—or it could start a preventive war. Deterrence relies, at bottom, on the assumption that an adversary is not suicidal, but this Administration suspects that Kim’s recklessness could trigger his own destruction. The official said, “Saddam Hussein was not suicidal, but he committed suicide.” In 2003, as the U.S. threatened to attack Iraq, Saddam was surrounded by sycophants and cut off from reliable information. He doubted that America would actually launch a full-scale attack, and, as a result, he miscalculated the odds of destroying himself and his regime.

A warm drizzle was falling on Pyongyang the morning after my arrival, as we left the Kobangsan Guest House to see the city. More than any other capital that has been marooned by politics—Havana or Rangoon or Caracas—Pyongyang presents a panorama from another time. Soviet-era Ladas and ancient city buses ply the streets, while passengers stick their heads out the windows in search of cool air. Buildings are adorned with Korean-language banners hailing the “Juche ideology,” the official state credo, which glorifies self-reliance and loyalty. On an embankment near a major intersection, workers in gray coveralls were installing an enormous red sign that praised the “immortal achievements of the esteemed Supreme Leader, comrade Kim Jong Un, who built the nuclear state of Juche, the leader in rocket power!”

Pyongyang is a city of simulated perfection, without litter or graffiti—or, for that matter, anyone in a wheelchair. Its population, of 2.9 million, has been chosen for political reliability and physical health. The city is surrounded by checkpoints that prevent ineligible citizens from entering.

For decades, there were few cars on the streets, but now frequent foreign visitors marvel at the growth in traffic. Pyongyang is the emptiest, quietest capital in Asia, but it is changing, slowly, driven by the legacy of famine. Between 1994 and 1998, a combination of mismanagement, droughts, and flooding paralyzed North Korean food production, killing up to three million people. Hundreds of thousands went to China in search of food and work, and many returned to their families having seen a better quality of life.

Since the famine, “the majority of today’s North Koreans have learned to lead an economic double life in order to make ends meet,” according to “North Korea Confidential,” a study of markets and daily life, by Daniel Tudor and James Pearson. North Koreans, outside their state-assigned jobs, sell homemade noodles in thriving markets; they drive private buses; they rent out apartments by the hour for courting couples. Government insiders import housewares, medicine, and luxury products from China, giving rise to an entrepreneurial élite known as donju—“masters of money.” Kim has allowed limited economic reforms, letting people accumulate profits, which has fuelled the growth of black markets, including in real estate. Officially, there is no private homeownership, but, in practice, people pay for better units. An ordinary one-bedroom apartment in Pyongyang costs three or four thousand dollars; the most luxurious offerings sell for hundreds of thousands.

The weak enforcement of sanctions, and continued demand from China and Russia, has allowed North Korea’s economy to grow with surprising speed in recent years. According to South Korea’s central bank, North Korea’s G.D.P. grew an estimated 3.9 per cent in 2016, the fastest pace since 1999. (South Korea’s, by comparison, grew 2.8 per cent.)

On the streets of Pyongyang, there are flashes of modernity, even style. Some women can be seen wearing stilettos and short skirts, though these can be no higher than two inches above the knee, according to Workers’ Party regulations. (Jeans are still practically taboo, because of their association with America.) Now and then, I saw people hunched over cell phones. Since 2013, Pyongyang has had 3G mobile service, but most people have access only to North Korea’s self-contained intranet, which allows them to send e-mail inside the country and to look at some Web sites. But many North Koreans have had some exposure to Chinese, American, and South Korean entertainment, smuggled over the border on SD cards that are small enough to be inserted into a phone. (Kim Jong Un, sensing the danger that information poses, has denounced foreign movies and music as “poisonous weeds.” In 2015, his government warned that people caught with illegal videos could face ten years of hard labor.)

“The regime does not really want the living standards to rise fast and too much, because that could shake the nation,” Alexandre Mansourov, a North Korea analyst who earned an advanced degree at Kim Il Sung University and served as a Soviet diplomat in Pyongyang in the nineteen-eighties, told me. “It’s the revolution of rising expectations. They want to manage that.” Kim Jong Un promotes economic growth on his own terms. Every year since assuming power, he has unveiled a new residential complex in the capital, as well as theatres, a water park, and a new airport. This past spring, he attended the opening of more than three thousand new apartments on Ryomyong Street, and Mr. Pak was eager to show off the buildings. The green-and-white complex, which includes a seventy-story high-rise, has circular columns and bulging round balconies that give it a “Jetsons”-like look.

I passed couples whispering on park benches, and a grandmother following a toddler across fresh asphalt. A black Lexus, buffed to a high shine, honked its way through pedestrians. (Officially, most private cars are provided as gifts from the Supreme Leader, but insiders acquire cars by registering them in the names of state enterprises.) We came upon a van fitted with oversized loudspeakers on its roof. Pak said that the message being played was a “warning about American aggression.” He explained, “We have a propaganda unit in every district.” Nobody seemed to be paying much attention.

I spent ten years abroad as a foreign correspondent, mostly in China, Egypt, and Iraq, but little of that experience is comparable to reporting in North Korea. Based on my requests, the government gave me an itinerary and then escorted me from place to place. A reporter cannot venture out into the city or the countryside independently without risking detention or compromising the safety of any North Korean who coöperates. But the country has become incrementally more open to scholars and reporters. In 2000, journalists who accompanied Secretary of State Madeleine Albright on a visit travelled on a bus with covered windows and were warned not to take photographs. Today, the constraints are more subtle. I asked to visit an ordinary apartment in Pyongyang—any apartment—and was told that it was “too late to be arranged.”

I’d asked to see some schools, so I was taken to the Pyongyang Orphans’ Secondary School—a brand-new brick-and-steel complex with an Astro-Turf field for four hundred lucky pupils. The principal, Pak Yong Chul, ushered me into a permanent exhibition on the ground floor, dedicated to the two-hour visit that Kim paid to the school on July 2, 2016. The walls of the exhibition are lined with photographs of Kim in his signature gray suit, striding through the facilities, holding an unlit cigarette between his fingers. On a large wall map, a red dashed line marked Kim’s route through the corridors. The students visit the exhibition every month, to “move along in the footprints of the Supreme Leader,” the principal said.

I stood in front of a large photo of Kim touching a fuzzy red blanket. The principal stepped aside, and, with a flourish, revealed, in a Plexiglas box, the blanket. “He personally touched it,” he said. So it was with other specimens—the white painted chair that he blessed with his presence in the lunchroom; the simple wooden chair from the language lab, on which he rested from his labors—all preserved under glass, like the relics of a saint. I asked Pak Yong Chul how it felt to be visited by the leader, and his eyes widened. “That moment is unforgettable. I would never have dreamed of it,” he said.

Upstairs, I stopped by a history class, where ten- and eleven-year-old students sat in perfect rows. I introduced myself as an American and asked if anyone had a question for me. After a long pause, a skinny boy with two medals pinned to his chest stood and asked, “Why is America trying to provoke a war with us? And what right do they have to block us from building our own nuclear weapon?” This did not seem the occasion for rigorous analysis or debate. I mumbled some bromides about hoping that things would get better. The boy seemed unimpressed.

II. A Marxist Emperor

Before Kim’s accession, in 2011, he was almost completely unknown, even inside the country. His name had first appeared in the state press a couple of years earlier. The C.I.A. had little more than a single photo of him—as an eleven-year-old, according to Sue Mi Terry, a former Korea analyst at the agency. In 2008, when Kim Jong Il suffered a stroke, Randal Phillips, a senior C.I.A. officer overseeing operations in Asia, met a Chinese counterpart to share analyses, as they sometimes did. But Phillips discovered that Chinese intelligence “didn’t know what was happening,” he told me. “I think the Chinese know a hell of a lot less than people assume.” Compared with other American adversaries, North Korea is the “hardest target,” Terry said. “There’s no other country that’s like that,” she told me. “It’s just pieced together.”

Kim Jong Il suffered a heart attack, and died in December, 2011. At the funeral, Kim Jong Un, the second youngest of his seven children, appeared pale and childlike, weeping as his father lay in an open casket. Afterward, he led the pallbearers, including spy chiefs and Army bosses, decades his senior. Some prominent analysts predicted that Kim would not be as secure in his power as his grandfather and father had been; his regime could succumb to a coup or could implode for other reasons. Victor Cha, who had been George W. Bush’s lead adviser on Korea, wrote in an Op-Ed in the Times, “North Korea as we know it is over.” Cha told me recently, “I thought he would not last for more than a couple of years.”

At first, Kim worked under the guidance of three Party elders who served as “regents,” according to Ken Gause, a specialist in North Korean politics at the Center for Naval Analyses, a nonprofit research group in Washington. Kim and his mentors made shrewd choices that helped to establish his authority. Physically, he transformed himself into a near-reincarnation of his grandfather, Kim Il Sung, who was much more popular than Kim Jong Il. He bore a natural likeness to his grandfather, and, to accentuate it, he gained weight, cut his hair in a shorn-sided pompadour, and began wearing horn-rimmed glasses and a panama hat. (When foreign media suggested that he had undergone surgery to enhance the similarity, the state news agency condemned the speculation as “sordid hackwork by rubbish media.”)

Politically, Kim put himself forward as a more candid and practical leader. His father never permitted discussion of flaws in the socialist paradise, but in April, 2012, Kim acknowledged the failure of a rocket that, upon launch, quickly crumbled into the Yellow Sea. The next month, during a televised inspection of the Mangyongdae amusement park, he made a show of bending down to pull weeds from the sidewalk, and chastising the managers: “How could you not see these? How could you be so negligent and complacent?”

Kim gradually shed the control of his regents and presented himself as a socialist of the modern age—he was seen in the North Korean media flying on a luxuriously appointed Ilyushin jet, typing on a MacBook, and enjoying an amusement-park ride at the Rungna People’s Pleasure Ground. He appeared in public with his wife, a stylish former cheerleader named Ri Sol Ju, whom he married in 2009. (They are believed to have three children.) As always, the propagandists were attentive: foreign analysts who track the use of Photoshop on North Korean state images say that official pictures of Kim are often altered around his ears, possibly to mask some sort of blemish.

Kim also sought to convey an ease with brutality, and embarked on North Korea’s most violent Party purge in decades. He executed two of his father’s seven senior pallbearers—his uncle Jang Song Thaek and the Army chief Ri Yong Ho—and expelled three others. His father had also executed senior cadres when he came to power, but killing Jang, an influential family member with deep ties to China, was an act of extraordinary boldness. The charges against Jang ranged from “treachery” to applauding “halfheartedly” when Kim entered the room. Many of Jang’s children and aides were also put to death, in ways that were intended to capture attention. Some were killed by flamethrowers; others were shot by anti-aircraft guns before outdoor audiences. (Media reports that Jang himself was fed to dogs proved to be false. He was executed by firing squad.)

Evan Medeiros, who was President Obama’s chief Asia adviser, told me that Kim Jong Il’s “approach to managing élites appeared to be more incentive-based than coercion-based, making sure that they all got goodies and spoils.” He went on, “The son’s approach appears to be ‘If you screw with me, I’m just going to kill you—and I’m going to kill you in a really nasty way.’ ”

That principle was expressed most dramatically earlier this year. The target was Kim’s estranged half brother, Kim Jong Nam, who had been living in semi-exile in Macau for more than a decade. In recent years, Kim Jong Nam had given interviews that were critical of the young leader, telling Yoji Gomi, a Japanese journalist, that North Korea was “likely to become weak under the third generation.” In a fateful comment, he called his half brother “just a figurehead.”

On the morning of February 13th, Kim Jong Nam was at Kuala Lumpur International Airport, in Malaysia. At home in Macau, the Chinese government provided security guards, but he travelled alone. An airport security camera captured his arrival and movements. He wore jeans and a summer blazer, and carried a backpack. As he stood before a check-in kiosk, two young women smeared liquid on his face, and then fled. Agitated, he approached a security guard. He grew dizzy and was taken to an airport clinic, where his condition rapidly deteriorated. In a photograph, he is slumped in a chair, arms splayed, eyes closed. He died in an ambulance, less than twenty minutes after the attack. Based on samples taken from his eyes and skin, Malaysian authorities accused North Korea of its first known assassination by the nerve agent VX, a tasteless, odorless chemical weapon. South Korean and Japanese media reported that he may have enraged his brother by preparing to defect or by aiding foreign intelligence services.

The killing caused a diplomatic crisis: North Korea demanded the return of the body and of several North Korean citizens, who were sought by police for questioning. When those demands were refused, North Korea sealed its borders to departing Malaysians, trapping nine embassy workers and their families. After two weeks, Malaysia released Kim Jong Nam’s body, and North Korea allowed the workers and their families to leave. The two women involved in the attack, who face first-degree-murder charges, are in custody in Malaysia; they have told investigators that they worked in local night clubs and were paid ninety dollars each for what they thought was a TV-show prank. After the attack, the women washed their hands, suggesting that they may have been given separate, harmless chemical components that became toxic when mixed together. They are scheduled to go on trial in October.

Six years into Kim Jong Un’s reign, some analysts in Seoul argue that senior Party officials can overrule or direct him, but U.S. intelligence believes that Kim is in sole command. The assassination of the half brother could not have happened without Kim’s approval, a U.S. official who works on Korea told me. “He’s the top decider, you might say,” the official said. “He’s the only guy that counts.” Many analysts worry that, as Kim moves deeper into confrontation with America, he does not have advisers who speak candidly to him. “We can’t identify an internal or external channel of information flow that’s effective in communicating the risks of the course that he’s on,” Scott Snyder, a Korea specialist at the Council on Foreign Relations, told me. “What general is going to be willing to risk his stars, if not his life, in order to tell Kim Jong Un he’s doing the wrong thing?”

The U.S. has investigated the question of Kim Jong Un’s hold on power and has found no evidence of a potential coup or a challenge from disaffected élites. At the moment, Kim’s most visible vulnerability is his health: he is overweight and perhaps diabetic. In North Korea, the leader’s health is closely monitored by an agency called the Longevity Research Institute. Barring the unforeseen, Kim could rule North Korea for decades.

On the way to lunch one afternoon in Pyongyang, I noticed that the latest American threats had already been inscribed on the cityscape. A full-color billboard depicted a barrage of missiles descending on a bombed-out shell of the U.S. Capitol. Across the wreckage of Washington, it said, according to Pak’s translation, “Preëmptive Strike” and “Military Option.”

In the days after the President’s “locked and loaded” remarks, the U.S., following the doctrine of a standoff, was seeking to convey ambiguity—the sense that North Korea should tread carefully, because it doesn’t know what might trigger a violent American response. But the message was getting garbled en route to Pyongyang. That morning, we had awoken to discover that Mattis and Secretary of State Rex Tillerson had published a joint op-ed in the Wall Street Journal that was clearly an attempt to ratchet down the tension. They wrote, “The U.S. has no interest in regime change or accelerated reunification of Korea.”

Pak, who is one of the government’s seasoned interpreters of American media, had a hard time following it all. In the car, he turned and asked, “How common is this, for the Secretary of State and the Defense Secretary to write a joint editorial?” Not very common, I said. He nodded, and turned back around. He could not understand how the two Cabinet members could so clearly contradict the President. At other points during the week, Pak tried to clear up some confusing details about the American media. “So the Wall Street Journal is conservative?” he asked. The editorial page is conservative, I said, but the news coverage is straight. He took this in and nodded again.

Occasionally, Pak misread something that was hard to discern from far away. He told me, “The United States is a divided country. It has no appetite for war.” On some level, that was true—the United States is a divided country, and it is tired of fighting wars in the Middle East, in South Asia—but he would be wrong to assume that these facts would, with absolute assurance, prevent the Trump Administration from launching a strike on North Korea.

We pulled up to a large blue-and-white boat that doubles as a restaurant, moored on the banks of the Taedong River. A sign over the entrance memorialized two visits by the Supreme Leader: “General duty ship Moojige received on-the-spot guidance by the esteemed comrade Kim Jong Un.” The restaurant’s distinguishing charm is that you can catch your own lunch in its tanks. On the way to our table, we passed a man standing on a ladder, holding a net, trying to nab a large fish with long whiskers. We reached a dining room where several tables were occupied by families, whose members ranged in age from a grandfather in a Mao-style suit to a couple of kids chasing each other around the table.

We ordered beef, cold noodles, rice cakes, and sashimi. A television in the corner was tuned to the main state channel. Three other channels, devoted to sports, entertainment, and education, broadcast only occasionally. Pak said that we were watching a classic North Korean drama called “The Lighthouse.” He patiently explained the plot: “A man lived alone on a remote island with a lighthouse. Under the Japanese, he was like a slave, but, when the Great Leader Kim Il Sung came to power, he said this man should be acknowledged, and—”

The movie cut off abruptly and a matronly news anchor appeared on the screen.

“There’s news,” Pak said.

The broadcast showed photographs of Kim Jong Un in a dark pin-striped suit, surrounded by military men in uniform. The announcer reported that the missile unit had been tasked with preparing to strike the Pacific Ocean near Guam. Another photograph showed Kim beside a screen bearing a satellite image of Andersen Air Force Base, in Guam. The announcer quoted Kim as saying that he “would watch a little more of the foolish and stupid conduct of the Yankees” before making his final decision to launch. The segment ended with orchestral music over a video montage of missiles shooting from a launch pad, rockets blazing out of their launchers, and soldiers cheering as fighter jets screamed overhead. I glanced around the room and noticed that the other diners were engrossed in lunch.

I was confused. “So is he going to launch them or not?” I asked.

“I don’t know,” Pak said. “It depends on whether the United States sends another nuclear asset, like a B-1B, over the Korean Peninsula.”

“Does the U.S. know that’s the determining factor?” I asked.

“We haven’t told them! But they should know, because we said they should not send any further ‘nuclear provocations.’ ”

The mentions of war and weaponry were everywhere: on television, on billboards, in the talk of well-rehearsed schoolchildren. When I attended a show at Pyongyang’s Rungna Dolphinarium, in which dolphins flipped and jumped and performed tricks, the finale featured a video montage that included the image of a missile soaring across the sky. I asked Pak what connected dolphins with missiles. He said, “It’s inspiring to the people. We’re going to have everything we want. A dolphinarium. Nuclear weapons. One by one.”

At lunch, I asked Pak, “If your country would be destroyed in a nuclear exchange, why are you really entertaining the idea?”

North Korea, he said, is no stranger to devastation: “We’ve been through it twice before. The Korean War and the Arduous March”—the official euphemism for the famine of the mid-nineties. “We can do it a third time.” The argument is embedded in North Koreans’ self-image. They are taught to see themselves as inhabitants of a land shaped by a history of suffering, a sense of hostile encirclement, and a do-or-die insistence on survival.

But, to state the obvious, I said, risking a premature end to a friendly meal, a nuclear exchange would not be comparable.

“A few thousand would survive,” Pak said. “And the military would say, ‘Who cares? As long as the United States is destroyed, then we are all starting from the same line again.’ ” He added, “A lot of people would die. But not everyone would die.”

“We must envelop our environment in a dense fog,” Kim Jong Il once said, “to prevent our enemies from learning anything about us.” As a result, interested parties have to be creative. The South Korean intelligence service employs lip-readers to watch what Kim says away from the microphones at political events. To chart who is gaining and losing power, American scholars and analysts, like Cold War Kremlinologists, monitor the choreography of official funerals and dissect photo captions and propaganda reports. Over time, those efforts have started to cut through the fog around North Korea’s first family.

The Kim dynasty began in 1945, after the defeat of Japan. In a hasty redrawing of the map, the Americans and the Soviets divided the Korean Peninsula; in effect, each would control half. The Soviets installed Kim Il Sung, a nationalist guerrilla who had been living in the Soviet Union, as the leader of North Korea. After the humiliations of occupation and war, Kim presented himself as a Marxist emperor of sorts, who would revive Korea’s racial superiority and rebuild the nation as a fortress, impenetrable to imperialists. He restricted the entry of foreigners and curtailed his people’s freedom to leave or dissent. As he aged, Kim Il Sung sought to avoid the havoc that followed the deaths of Stalin and Mao by appointing his son as his successor, in the first hereditary transition in the Communist world. But Kim Jong Il, who assumed power in 1994, was not a natural demagogue. He was a cinéaste, plump and sedentary, who made his own version of “Godzilla.” (His favorite films also included “Rambo” and “Gone with the Wind.”)

Kim Jong Il grew isolated and paranoid. He allowed his voice to be heard in public only once, when he said, at a 1992 parade, “Glory be to the heroic soldiers of the Korean People’s Army!” On foreign trips, his aides brought home his feces and urine, to prevent foreign powers from hijacking the waste and evaluating his health. He was five feet two inches tall, and insecure about his height. In 1978, he ordered the kidnapping of his favorite South Korean actress, Choi Eun-hee, and greeted her by saying, “Small as a midget’s turd, aren’t I?” (Choi was forced to act in North Korean films until 1986, when, during a trip to Vienna, she escaped.) Jang Jin-sung, a poet and a high-ranking propagandist who defected to South Korea in 2004, told me that, when he was brought to meet Kim Jong Il, an aide instructed him, “Don’t look him in the eye. Look at the second button down from his collar.” Jang went on, “Before you met him, you were given a moist towelette to wash your hands and asked to remove your wristwatch or any metal in case it could do him harm.”

And yet Kim Jong Il came closer than any other North Korean leader to forging peace with the United States and ending his country’s isolation. Madeleine Albright, the only U.S. Secretary of State who has visited Pyongyang, spent more than twelve hours with Kim over two days, in 2000, negotiating the terms of a deal regarding his missile program. She found him odd—he personally choreographed a dance that was performed for her delegation—but also pragmatic and well informed. When members of the delegation asked highly technical questions, he answered many of them without consulting experts. Wendy Sherman, a diplomat who accompanied Albright on the trip, and later became President Obama’s chief negotiator with Iran, sensed the single-mindedness that has driven North Korea to acquire nuclear weapons. “We think in two-year, four-year, six-year time frames. They don’t. They’ve had a long-term vision since Kim Jong Il’s father, and they have stuck with it,” she told me.

In the final months of the Clinton Administration, Albright and Sherman believed that Kim was close to accepting a freeze on long-range missile tests. But the disputed election of 2000, and Clinton’s pursuit of a deal in the Middle East, consumed the Administration’s final weeks. They never returned to Pyongyang. Sherman told me, “If our team had gone, and if Kim agreed to our terms, I would have had a date in my pocket on which the President of the United States would have come.”

Once in office, George W. Bush declined to reaffirm a Clinton-era communiqué that pledged “no hostile intent” toward North Korea. Then, in his 2002 State of the Union address, Bush included North Korea, along with Iran and Iraq, in his famous formulation, the “axis of evil.” The relationship has deteriorated ever since. In 2009, when Clinton visited Kim to secure the release of two imprisoned journalists, Kim lamented that, once Bush came in, “we found ourselves missing the earlier, better relationship with the previous Administration.” According to American notes from the meeting, which were later divulged by WikiLeaks, Kim added, “The United States would have had a new friend in Northeast Asia in a complex world.”

For all Kim Jong Il’s eccentricity, he cultivated his relationship with America in ways that his son has not. Jerrold Post, who founded the C.I.A.’s psychological-profile unit, and later studied Kim Jong Il’s decision-making, told me, “He always seemed to know the boundaries of his adversaries’ tolerance for provocation. He would go so far, then pull back just in time. He had finely tuned antennae.” Post said that he worries that Kim Jong Un has been thrust into a complicated scenario with little time to hone those skills. “His father had two decades in the wings before he formally took over,” Post said. “The son had two years.”

There was nothing preordained about which of Kim Jong Il’s children would run the country. Evans Revere, the former Korea expert at the State Department, said that Kim Jong Un became the successor largely on the basis of attitude and aggression. When Kim was a child, he would wear a Soviet military uniform on his birthday. The palace staff took to calling him Comrade General. He gave off an “inner strength,” according to Kenji Fujimoto, a Japanese chef who spent part of his time as a playmate for the children. Fujimoto, who later wrote a memoir, entitled “Kim Jong Il’s Chef,” gave the young Kim video games and remote-controlled cars as gifts and, because the boy loved basketball, arranged for his sister to send VHS tapes of Chicago Bulls games.

In 1996, Kim joined a brother, Jong Chul, in Bern, Switzerland; they stayed with an aunt. At school there, Kim went by a pseudonym, Pak Un, and was introduced to other students as the son of the North Korean Ambassador. “One day, he said to me, ‘Yeah, I am the son of the leader of North Korea.’ But I didn’t believe him, because it was a normal school,” his classmate João Micaelo recalled, in a television interview. “He was very quiet. He didn’t speak with anyone. Maybe it was because most of the people, they didn’t take the time to understand him. He was competitive at sports. He didn’t like to lose, like every one of us. For him, basketball was everything.” Kim drew pictures of Michael Jordan and slept with a basketball, according to Ko Yong Suk, the aunt who cared for him. She took him skiing in the Alps, swimming on the French Riviera, and to the Disney park in Paris. He showed flashes of stubbornness. If he was scolded for not studying, he’d refuse to eat. “He wasn’t a troublemaker, but he was short-tempered,” Ko told the Washington Post last year. (She and her husband defected to the U.S. and now run a dry-cleaning business, under assumed names.)

When it came time for Kim Jong Il to choose an heir, his four daughters were ineligible, because of their gender. His eldest son, Jong Nam, was more a playboy than a statesman, and, in 2001, he was caught trying to enter Japan on a forged passport, to take his four-year-old son to Tokyo Disneyland. The next-oldest son, Jong Chul, was reserved and gentle. While in Switzerland, he had written a poem called “My Ideal World,” which began, “If I had my ideal world I would not allow weapons and atom bombs anymore. I would destroy all terrorists with the Hollywood star Jean-Claude Van Damme.” According to Fujimoto, Kim Jong Il said that Jong Chul was unfit to rule “because he is like a little girl.” (He now works as an aide to his brother, and is thought to be his natural successor.)

That left Jong Un, who had received a degree in physics from Kim Il Sung University, had trained as an artillery officer, and was active in security and political work. In 2009, North Korea specialists began hearing that Jong Un, then twenty-five, was the likely successor. “He had never been in charge of anything, had never checked any of the boxes that you would normally expect someone to check on their way up through the ranks,” Revere said. “But clearly he had some personality characteristics and traits that appealed to his father, and those included a level of authority and aggression and self-confidence—some traits that his father didn’t have.”

Before assuming power, Kim involved himself in a brazen military operation that provided a preview of his tolerance for risk, according to U.S. intelligence. In March, 2010, the North torpedoed a South Korean naval vessel, the Cheonan, killing forty-six personnel. It also shelled Yeonpyeong Island, killing two people. These acts could have generated a fierce response, but, in the end, Seoul did not retaliate.

Alexandre Mansourov, the former Soviet diplomat in Pyongyang, told me that Kim’s role in the attacks reassured élites that he wasn’t averse to confrontation. “It was domestic positioning,” Mansourov said. “He needed to prove to them and his father that he could stand up.” That fall, Kim was promoted to the rank of general and made his first public appearance by his father’s side, signalling to the world that he was the chosen successor.

In his rapid rise, Kim acquired defining habits of mind. Mansourov said, “He’s a person who was never told no. Nobody drew the red line, and said, ‘Not a step further.’ Nobody punched him in the face, made him feel hurt. We say, ‘A man begins to grow his wisdom tooth when he bites more than he can chew.’ With Kim Jong Un, he has never yet bitten more than he can chew. Whatever he sets his sights on he gets. He keeps pushing, and pushing, and pushing. We don’t know where his brakes are, and I suspect he doesn’t know where he can stop.”

III. “Single-Hearted Unity”

After a couple of days in Pyongyang, I was eager to get some glimpses of life beyond the capital. My minders agreed to an outing. Up before dawn, we climbed into the Toyota and headed toward the demilitarized zone, which marks the border with South Korea. Leaving Pyongyang, we passed through a checkpoint, and smooth asphalt eventually gave way to potholes brimming with rainwater. The nation’s wealth and modernity, such as it is, is largely limited to the capital. The road emptied first of cars, then of bicycles, until we passed only clusters of farmers. A woman balancing a load on her head walked along railroad tracks to a point unseen. Without the industrial haze that hovers over much of East Asia, the North Korean landscape is an incandescent green. Eighty per cent of the country is mountainous. (American military planners liken the terrain to Afghanistan’s.)

We stopped to stretch our legs beside a closed restaurant and spotted two busloads of foreign tourists. On September 1st, American tourists would be banned from visiting North Korea, under a State Department order prompted by the death of Otto Warmbier, a University of Virginia student who had been convicted of “a hostile act against the state,” for trying to remove a propaganda poster from the wall of a hotel in Pyongyang. In June, American officials, having discovered that Warmbier had been in a coma for more than a year, secured his release. He died six days after returning home.

I mentioned the upcoming ban, and Pak said that it was a pity, because, after years of internal deliberations, North Korea had been preparing to accept more foreign visitors. “The military used to be very unhappy about tourists coming here, because they might see the secrets of what we’re doing,” he said. “But now we have gained strength.”

In recent months, I’d spoken to American negotiators involved in Warmbier’s case, and they questioned why it had ended tragically. (In the past two decades, at least sixteen Americans have been detained while visiting North Korea, but no others have suffered as much harm.) Warmbier was arrested in January, 2016. After a show trial, he was sentenced to fifteen years of hard labor. Pyongyang reported that Warmbier contracted botulism, was given a sedative, and entered a coma. But doctors in Cincinnati who treated him after his release found no traces of botulism. Many North Korea specialists wondered if he fell ill and was given a catastrophic overdose of medication. Others suspected that he was beaten or interrogated to the point of collapse, but that would be out of the ordinary; most American detainees in North Korea are not beaten, because they are considered bargaining chips.

Negotiators for the Warmbier family, such as Bill Richardson, the former governor of New Mexico, had been frustrated in their efforts, and I asked Pak why the government had stonewalled them. Pak blamed an Obama Administration decision, in July, 2016, to impose personal sanctions on Kim Jong Un and other top officials. “Obama blacklisted our leaders, and smeared them by name,” Pak said. “At that point, we could not accept it. We cut off the New York channel and we adopted wartime measures. From then on, we said, the situation will stay as is.”

I told him that Warmbier’s death had done more damage to North Korea’s reputation in the U.S. than he probably realized. Pak was unmoved. “He broke our rules, and we take that very seriously,” he said. That morning, the news from America was about the racist demonstrations in Charlottesville, and Pak explained, “In the D.P.R.K., the military thinks Americans come here and try to do whatever they want, like white supremacists are doing in the United States.” (Three Americans are still detained in North Korea: Kim Dong-chul was convicted of spying and is serving a ten-year sentence; Kim Hak-song and Tony Kim are being held on unspecified charges.)

By midmorning, we had reached the D.M.Z., an open gash across the Peninsula, a remnant of the Korean War. For most Americans, the war is overshadowed by other dramas of the twentieth century, but it’s impossible to understand North Korea’s hostility toward the U.S. today without looking at the history. In June, 1950, North Korea, seeking to unify the Peninsula under Communism, invaded the South. The United States and China entered the war on opposing sides, and by 1953 President Eisenhower had concluded that the conflict had reached a stalemate. That July, after more than four million people had been killed, the sides signed a ceasefire, but not a peace treaty.

The regime’s efforts to cultivate paranoia and contempt for America are rooted in the scale and the devastation of the bombing during the war. Dean Rusk, who later became Secretary of State, recalled, in an oral history in 1985, that the United States bombed “every brick that was standing on top of another, everything that moved.” General Curtis LeMay, the head of the Strategic Air Command during the Korean War, told the Office of Air Force History in 1984, “Over a period of three years or so, we killed off—what—twenty per cent of the population.” After the ceasefire, each side walked back two thousand metres, creating the D.M.Z., a buffer zone two and a half miles wide. Large numbers of troops are stationed on both sides, and outbreaks of violence have killed several hundred soldiers over the years. In the most recent incident, in August, 2015, two South Korean soldiers were wounded by land mines.

The Korean People’s Army assigned Lieutenant Colonel Pang Myong Jin to show me around. Pang is in his late thirties, with prominent cheekbones and a sharp chin. He wore a green uniform and an officer’s cap as broad as a dinner plate. We drove down a narrow road, through a gap in the tank traps and the barbed wire, to a clearing in the forest, which the North Koreans have turned into a shrine, called the North Korea Peace Museum. In their version of the conflict, the United States started the Korean War; the singular leadership of Kim Il Sung led to a humiliating defeat of the Americans, who have tried, ever since, to provoke another war. “This was the first time that the U.S. was defeated by the Korean people,” Pang told me. He led me to a tall stone tablet with a Korean inscription:

The great leader, Comrade Kim Jong Il, visited this spot four times, including on July 19, 1972. The esteemed high commander, Comrade Kim Jong Un, visited on March 3, 2012. They taught us the valuable lesson of preserving and passing on this historic site—where invading Americans knelt before the people in surrender—to the next generation, in a reunified homeland.

Every country valorizes its war record, but North Korea’s mythology—the improbable victory, the divine wisdom of the Kim family, and America’s enduring weakness and hostility—has shaped its conception of the present to a degree that is hard for the rest of the world to understand. In something close to a state religion, North Korea tells its people that their nation may be small, but its unique “single-hearted unity” would crush a beleaguered American military. That’s a volatile notion. Robert Jervis, a Columbia University political scientist, who studies the origins of war, once observed, “War is most likely if you overestimate others’ hostility but underestimate their capabilities.” It can be hard to know where North Korea’s reverie ends and realism resumes.

At our last stop, we drove through a grove of ginkgo trees, and arrived at a blue-painted hut that straddles the border with South Korea. North Korean guards in helmets watched us approach. When the two sides hold negotiations, they meet at a heavy wooden table that sits in both countries. I took a seat. “The microphones are the dividing line,” Pang said. I walked across the hut to stand, for a moment, in South Korea. When we stepped back outside, Pang said, “This is a very dangerous place, but the respected leader came here during the military exercises, at the highest level of tension. Do you think Trump would dare to come here?”

Yes, I said. He looked disappointed.

I asked Pang if he thinks the U.S. and North Korea will find themselves at war again. He reminded me that Kim had threatened to fire missiles into the Pacific Ocean. “We will fire a warning shot at Guam, and if that doesn’t work then we will fire a warning shot at the mainland United States. We want to achieve world peace, but if this isn’t possible then we are prepared for war.”

If you fire at Guam, I asked, how do you expect the U.S. to respond? He thought for a moment. It was quiet, except for the drone of cicadas. Then Pang cited a comment by Senator Lindsey Graham, of South Carolina, in a recent appearance on the “Today” show, which had filtered through translations and reached Pang more or less intact. Graham recounted his conversations with Trump, in which the President said he was prepared to strike Korea because the casualties will be “over there.”

“Trump said if there is war, then it will happen in the D.P.R.K., not in the U.S.,” Pang said. “So clearly he is preparing for war. He understands what he’s saying.”

What, exactly, are America’s options with North Korea? Many Korea specialists in Washington favor a major increase in pressure tactics, known as “strategic strangulation.” The U.S. would expand the use of cyber hacking and other covert methods to disrupt missile development and unnerve the government; it would flood the North with smuggled flash drives loaded with uncensored entertainment and information. It would also attempt to close off North Korea’s illicit trade networks, by interdicting ships, expanding sanctions against Chinese companies, and freezing the assets of individual leaders. “Make hundreds of millions of dollars of North Korean deposits in a Swiss bank disappear,” Evans Revere said. “The goal of this is not to cause the collapse of the regime. The goal of this is to convince the North Koreans that collapse is just over the horizon, and, if Kim Jong Un is a rational actor, then he will understand that.” Critics of the plan say that North Korea has perfected its ability to absorb pain, and that the plan is not fundamentally different from what previous Administrations have attempted.

There is also scattered support for a less confrontational option, a short-term deal known as a “freeze for freeze.” North Korea would stop weapons development in exchange for a halt or a reduction in U.S.-South Korean military exercises. Proponents say that a freeze, which could be revoked if either side cheats, is hardly perfect, but the alternatives are worse. Critics say that versions of it have been tried, without success, and that it will damage America’s alliance with the South. Thus far the Trump Administration has no interest. “The idea that some have suggested, of a so-called ‘freeze for freeze,’ is insulting,” Nikki Haley, the U.N. Ambassador, said before the Security Council on September 4th. “When a rogue regime has a nuclear weapon and an ICBM pointed at you, you do not take steps to lower your guard.”

Outside the Administration, the more people I talked to, the more I heard a strong case for some level of diplomatic contact. When Obama dispatched James Clapper to Pyongyang, in 2014, to negotiate the release of two prisoners, Clapper discovered that North Korea had misread the purpose of the trip. The government had presumed that he was coming in part to open a new phase in the relationship. “They were bitterly disappointed,” he said. Clapper’s visit convinced him that the absence of diplomatic contact is creating a dangerous gulf of misperception. “I was blown away by the siege mentality—the paranoia—that prevails among the leadership of North Korea. When we sabre-rattle, when we fly B-1s accompanied by jet escorts from the Republic of Korea and Japan, it makes us feel good, it reassures the allies, but what we don’t factor in is the impact on the North Koreans.”

Clapper went on, “I think that what we should do is consider seriously, in consultation with South Korea, establishing an interest section in Pyongyang much like we had in Havana for decades, to deal with a government that we didn’t recognize. If we had a permanent presence in Pyongyang, I wonder whether the outcome of the tragedy of Otto Warmbier might have been avoided. Secondly, it would provide on-scene insight into what is actually going on in North Korea—intelligence.”

It is a measure of how impoverished America’s contact with North Korea has become that one of the best-known conduits is Dennis Rodman, a.k.a. the Worm, the bad boy of the nineties-era Chicago Bulls. Rodman’s agent, Chris Volo, a hulking former mixed-martial-arts fighter, told me recently, “I’ve been there four times in four years. I’m in the Korean Sea, and I’m saying to myself, ‘No one would believe that I’m alone right now, riding Sea-Doos with Kim Jong Un.’ ” Rodman’s strange bond with Kim began in 2013, when Vice Media, aware of Kim’s love of the Bulls, offered to fly American basketball players to North Korea. Vice tried to contact Michael Jordan but got nowhere. Rodman, who was working the night-club autograph circuit, was happy to go. He joined three members of the Harlem Globetrotters for a game in Pyongyang. Kim made a surprise appearance, invited Rodman to dinner, and asked him to return to North Korea for a week at his private beach resort in Wonsan, which Rodman later described as “Hawaii or Ibiza, but he’s the only one that lives there.” On his most recent trip, in June, Rodman gave Kim English and Korean editions of Trump’s 1987 best-seller, “The Art of the Deal.”

Ultimately, the Trump Administration must decide if it can live with North Korea as a nuclear state. During the Cold War, the United States used deterrence, arms control, and diplomacy to coexist with a hostile, untrustworthy adversary. At its height, the Soviet Union had fifty-five thousand nuclear weapons. According to the rand Corporation, the North Koreans are on track to have between fifty and a hundred by 2020; that would be less than half the size of Great Britain’s arsenal.

Susan Rice, who served as Obama’s national-security adviser, argued, in a Times Op-Ed last month, that the U.S. can “rely on traditional deterrence” to blunt North Korea’s threat. But McMaster is skeptical that the Soviet model can be applied to Pyongyang. He told me, “There are reasons why this situation is different from the one we were in with the Soviets. The North Koreans have shown, through their words and actions, their intention to blackmail the United States into abandoning our South Korean ally, potentially clearing the path for a second Korean War.”

If the Administration were to choose a preventive war, one option is “decapitation,” an effort to kill senior leaders with a conventional or even a nuclear attack, though most analysts consider the risks unacceptable. Such a strike could rally the population around the regime and cause a surviving commander to respond with a nuclear weapon. Another option is akin to Israel’s 1981 stealth attack on the Osirak nuclear reactor, the linchpin of Saddam Hussein’s nuclear-weapons development, which set back Iraq’s pursuit of nuclear weapons by at least a decade. “That’s a textbook case of a preventive war,” the senior Administration official told me.

But the comparison between Osirak and North Korea is limited. In 1981, Iraq had yet to make a bomb, and it had just one major nuclear target, which was isolated in the desert and relatively easy to eliminate. North Korea already has dozens of usable nuclear warheads, distributed across an unknown number of facilities, many of them hidden underground. Even destroying their missiles on the launch pad has become much harder, because the North has developed mobile launchers and solid-fuel missiles, which can be rolled out and fired with far less advance notice than older liquid-fuel missiles.

The Obama Administration studied the potential costs and benefits of a preventive war intended to destroy North Korea’s nuclear weapons. Its conclusion, according to Rice, in the Times, was that it would be “lunacy,” resulting in “hundreds of thousands, if not millions, of casualties.” North Korea likely would retaliate with an attack on Seoul. The North has positioned thousands of artillery cannons and rocket launchers in range of the South Korean capital, which has a population of ten million, and other densely populated areas. (Despite domestic pressure to avoid confrontation, South Korea’s President, Moon Jae-in, has accepted the installation of an American missile-defense system called Terminal High-Altitude Area Defense, or thaad.)

Some two hundred thousand Americans live in South Korea. (Forty thousand U.S. military personnel are stationed in Japan, which would also be vulnerable.) A 2012 study of the risks of a North Korean attack on Seoul, by the Nautilus Institute for Security and Sustainability, estimates that sixty-five thousand civilians would die on the first day, and tens of thousands more in the days that followed. If Kim used his stockpiles of sarin gas and biological weapons, the toll would reach the millions. U.S. and South Korean forces could eventually overwhelm the North Korean military, but, by any measure, the conflict would yield one of the worst mass killings in the modern age.

In dozens of conversations this summer, in the United States and Asia, experts from across the political spectrum predicted that, despite the threats from Trump and McMaster, the U.S. most likely will accept the reality of North Korea as a nuclear state, and then try to convince Kim Jong Un that using—or selling—those weapons would bring about its annihilation. John Delury, a professor at Yonsei University, in Seoul, said, “If, one day, an American President comes along—maybe Trump—who understands the problem is the hostile relationship, and takes steps to improve it, then the slow train to denuclearization could leave the station.”

Managing a nuclear North Korea will not be cheap. It will require stronger missile defenses in South Korea, Japan, Alaska, and Hawaii, and more investment in intelligence to track the locations of North Korea’s weapons, to insure that we pose a credible threat of destroying them. Scott Snyder, of the Council on Foreign Relations, said, “I think we’re going to end up in a situation where we live with a nuclear-capable North Korea, but it will be a situation that is incredibly dangerous. Because, at that point, any unexplained move that looks like it could involve preparations for a nuclear strike could precipitate an American preëmptive response.” Even that risk, by almost all accounts, is better than a war.

IV. “We’re Not Going to Die Alone”

On the morning of August 17th, I awoke and found a new tweet from @realDonaldTrump: “Kim Jong Un of North Korea made a very wise and well reasoned decision. The alternative would have been both catastrophic and unacceptable.” What decision was the President referring to? After poking around online, I discovered that Trump had picked up on Kim’s comment that he “would watch a little more the foolish and stupid conduct of the Yankees” before deciding whether to fire missiles at Guam. To Trump, this was Kim standing down. He was pleased. (A few days later, Trump told a rally in Phoenix, “He is starting to respect us.”) But, it seemed, Trump was misreading the signals. “He only read one half of the statement,” Pak said, in frustration.

That morning, I was scheduled to interview a senior diplomat named Jo Chol Su, who had served in the North Korean Embassy in Geneva before being assigned, recently, to work on the United States. We spoke at my hotel, seated in giant armchairs, beside an especially large pair of Kim portraits.

Jo arrived with a young colleague to translate for us and carried a sheaf of printed remarks. Jo asked if he could begin with “an overview of the current situation and the history” of relations between our countries. He studied my face and added, “I’ll make it brief.” He spoke for seventeen minutes, blasting the latest sanctions and hailing the ICBMs as a new era. “Today, we’ve got everything we need in our hands, and it’s preposterous to think that new sanctions and new threats will change anything.”

When he finished, I mentioned that, overnight, Trump had issued a tweet about Kim Jong Un. Jo looked stricken. There was nothing in his prepared remarks about it. He asked me to read it aloud, and he jotted it down as I read it. When I was done, Jo looked up and said, through his translator, “Once more, please.”

I read the tweet again. Jo stared at his paper. After a pause, he reiterated some of his speech and then improvised: “The U.S. should put an end to its high-handed practices and unilateral compulsion toward the D.P.R.K. and just leave us alone.”

Jo wrapped up with a grand farewell. “I know that The New Yorker is very influential and I’ve received good feelings through our dialogue today,” the translator said. “I’d be grateful if you just write articles which are conducive to the improved bilateral relations between the D.P.R.K. and the U.S.”

The three of us walked to the lobby. Jo lit a cigarette, ordered a coffee, and turned to me and said, in nearly perfect English, “I’m sorry—I should’ve asked first if you’d like a coffee. Can I order you one?”

Diplomats, no matter what their language skills, often use a translator on formal occasions, but I was impressed by how swiftly Jo eased out of his official mask. We chatted, and I asked him if he’d been to the United States. Never, he said. I had wondered what it must be like to experience the United States through the fog of Twitter. It turned out that it wasn’t much different from Americans trying to make sense of North Korea through its propaganda.

After breakfast one morning, Mr. Pak drove me to a subway station in downtown Pyongyang, and announced, “This is for the nuclear war.”

By now, I was accustomed to his chipper declarations about an imminent cataclysm, but this one baffled me. He explained, “Everything here has a dual-use purpose.” He pointed to an underpass, beneath an intersection, which he said can serve as a shelter. In the back yards of apartment blocks, residents can take cover in storage cellars. Surrounded by commuters, we boarded an escalator, heading down to the station.

Built in the seventies, with Russian help, the Pyongyang Metro lies a hundred metres underground, nearly twice as far as the deepest platform in the New York City subway. Pyongyang stations are equipped with large blast doors. “During the Korean War, we were threatened by nukes,” Pak said. In 1950, President Truman raised the possibility of using the atomic bomb in Korea. “It touched our people’s minds,” he said, adding, “We don’t want that to happen again. And now we’ve got nukes and we can comfortably say, ‘Let’s do it.’ ”

In the event of a nuclear war, American strategists assume that North Korea would first launch a nuclear or chemical weapon at an American military base in Japan or Guam, in the belief that the U.S. would then hold its fire, rather than risk a strike on its mainland. I mentioned that to Pak, but he countered with a different view. “The point of nuclear war is to give total destruction to another party,” he said. “There are no moves, no maneuvers. That’s a conventional war.”

When we reached the subway platform, we were treated to patriotic orchestral music playing on the loudspeaker. Broadsheet newspaper pages were hung behind glass for people to read while they waited for the train. The scene reminded me of thirty-year-old photos I’ve seen of Beijing. We rode the train awhile, and then got on the escalator for the long ascent to the surface.

I was glad to be back in the open air. We got in the Toyota, and Pak said, “If the U.S. puts sanctions and sanctions and sanctions and sanctions, if they drive us to the edge of the cliff, we will attack. That’s how the world wars have started.” He thought awhile and then said, “Don’t push us too hard, because you’re going to start a war. And we should say, we’re not going to die alone.”

This was a familiar refrain. Some of the American officials in Washington who are immersed in the problem of North Korea frequently mention the old Korean saying “Nuh jukgo, nah jukja!” It means “You die, I die!” It’s the expression you hear in a barroom fight, or from an exasperated spouse—the notion that one party will go over the cliff if it will take the other down, too. Krys Lee, a Korean-American author and translator, said, “My mother also used it on me!” Lee finds that it’s hard for Americans and Koreans to gauge each other’s precise emotions, because Koreans tend to use “more abstract, dramatic, and sentimental language.” She has heard that many Korean literature students find Raymond Carver—the most laconic of American authors—“very dry, and that he didn’t translate well.”

On my last morning in Pyongyang, I visited the Victorious Fatherland Liberation War Museum. Shortly after Kim came to power, he renovated and expanded it; the museum is now nearly three-quarters the size of the Louvre. Choe Un Jong, a captain in the Korean People’s Army, showed me around. We were the only visitors. (It was a Friday, when, Choe said, the museum is open only to foreigners.) A tall woman in her twenties, Choe had stylish wavy hair that fell to her shoulders. She said, apologetically, “Today I cannot show you all of the museum. It takes three or four days.”

We stood beneath a three-story granite statue of a barrel-chested young Kim Il Sung, looking indistinguishable from his grandson. I told Choe that I had trouble telling their statues apart. She was thrilled. “Without any explanation, people think that that’s Marshal Kim Jong Un!” she said. The exhibits made use of life-size wax figures: there was a Korean commando crouching in the woods, and a dead American soldier with his eyes rolled back and a raven picking at his chest. We walked past captured howitzers and tanks, and a U.S. plane that she said delivered “germ bombs” loaded with “malaria, cholera, and typhoid.” (That claim has been widely debunked.) Choe sat me down for a video called “Who Started the Korean War?,” in which the narrator said, “The Korean War was precisely a direct product of the aggressive foreign policy of the United States to dominate the world.”

The mythology was no surprise, but one exhibit contained a stark implication for the current crisis. Beside the museum, we boarded the U.S.S. Pueblo, a Navy spy ship that was captured in January, 1968, long after the end of the Korean War. The seizure—during a surge of hostilities not unlike the present—was an audacious gamble on North Korea’s part. One American crew member was killed and eighty-two were detained. Lyndon Johnson considered retaliating with a naval blockade or even a nuclear strike. But he was consumed by the war in Vietnam, and, in the end, he did not retaliate. After eleven months, the U.S. apologized for spying and won the release of the prisoners.

The Pueblo incident nearly started a war, but Kim Il Sung drew a powerful, and potentially misleading, lesson from it. In a private conversation in 1971, Kim told Nicolae Ceaușescu, the Romanian President, that the Pueblo and other standoffs had convinced him that Washington backs down. “The Americans don’t want to continue this fight,” he said, according to documents in Romania’s state archives. “They let us know it’s not their intention to fight the Koreans again.”

Van Jackson, a scholar of international relations who served in the Pentagon from 2009 to 2014, spent years analyzing the Kim family’s handling of crises, including the seizure of the Pueblo. The grandfather’s theory of victory still drives North Korea toward provocation, he said, but the regime also knows its limits; to survive, it chooses violence but avoids escalation. “When South Korea blares giant propaganda speakers at the North from the D.M.Z., North Korea fires warning shots nearby but doesn’t dare attack the speakers themselves,” he said. “When South Korean N.G.O.s send propaganda leaflets into North Korea using hot-air balloons—which really pisses them off—North Korea threatens to attack the N.G.O.s but instead just fires at the unmanned balloons.” In Jackson’s view, North Korea is not irrational, but it very much wants America to think that it is.

Jackson believes that the Trump Administration’s threat to launch a preventive war begins a new phase. “Trump may abandon the one thing that has prevented war in the past: U.S. restraint,” he told me. In embracing new rhetoric and rationale, the U.S. risks a spiral of hostility in which neither side intends to start a war but threats and intimidation lead to ever more aggressive behavior. Trump and Kim may goad each other into the very conflict that they are both trying to avoid.

In 1966, Thomas Schelling, the deterrence expert, wrote that brinkmanship hinges, above all, on “beliefs and expectations.” Our grasp of North Korea’s beliefs and expectations is not much better than its grasp of ours. To go between Washington and Pyongyang at this nuclear moment is to be struck, most of all, by how little the two understand each other. In eighteen years of reporting, I’ve never felt as much uncertainty at the end of a project, a feeling that nobody—not the diplomats, the strategists, or the scholars who have devoted their lives to the subject—is able to describe with confidence how the other side thinks. We simply don’t know how Kim Jong Un really regards the use of his country’s nuclear arsenal, or how much North Korea’s seclusion and mythology has distorted its understanding of American resolve. We don’t know whether Kim Jong Un is taking ever-greater risks because he is determined to fulfill his family’s dream of retaking South Korea, or because he is afraid of ending up like Qaddafi.

To some in the Trump Administration, the gaps in our knowledge of North Korea represent an argument against deterrence; they are unwilling to assume that Pyongyang will be constrained by the prospect of mutually assured destruction. But, if the alternative is a war with catastrophic costs, then gaps in our knowledge should make a different case. Iraq taught us the cost of going to war against an adversary that we do not fully understand. Before we take a radical step into Asia, we should be sure that we’re not making that mistake again. ♦

Due to an editorial error, an earlier version of this article misidentified Kim Jong Un’s birth order.

Reporting and photography for this piece was facilitated by a grant from the Pulitzer Center on Crisis Reporting.