The Demilitarized Zone (DMZ) on the border between North and South Korea is often described as the most dangerous place in the world. It’s a no man’s land 160 miles long and 2 1/2-miles wide, wrapped with electrical fencing and laced with antipersonnel mines.

At the so-called Joint Security Area, North and South Korean soldiers stare holes through each other, with the South Koreans behind reflective sunglasses. Almost 30,000 American troops are stationed there as a tripwire. If the North invades the South — as it has in the past and for more than five decades has sworn to do again — its soldiers will have to go through ours. You can go there today as a tourist from the South Korean side, a mere 35 miles from the capital Seoul, and nothing is likely to happen to you; but if war breaks out, this place will explode so catastrophically it will make the Iraq War look and feel like a lazy afternoon nap.

In mountainsides just north of the DMZ, the North has buried thousands of artillery pieces that can pound Seoul’s urban area, home to more than 25 million people, with as many as half a million shells in an hour. More than a million people could be killed, practically in an instant, even if nobody on either side uses nuclear weapons.

We haven’t been this close to total war with North Korea since the 1950s.

The North’s tyrant leader, Kim Jong Un, has dozens of atomic bombs (no one is entirely sure of how many) and claims he’s ready to test an exponentially more destructive hydrogen bomb. And for the first time ever, his intercontinental ballistic missiles may be capable of striking mainland United States.

The North Korean missile crisis, which these days feels like the Cuban missile crisis in slow motion, already has taken us well beyond the most dangerous threshold. North Korea isn’t an aspiring nuclear power. It already has arrived. Kim can kill as many American civilians in cities from Seattle to Chicago as he can in Seoul. It is too late to stop him. During a panel discussion at the University of Pennsylvania in late September, retired Navy Admiral James Stavridis, NATO’s former supreme allied commander in Europe, said he believes there is a 10 percent chance of a nuclear war breaking out between the United States and North Korea, and a 20-30 percent chance of them engaging in a conventional war.

Kim also has a massive stockpile of chemical weapons and has proven that he’s willing to use them. In February, two young women — one from Vietnam, the other from Indonesia — assassinated his half-brother, Kim Jong Nam, in the international airport in Kuala Lumpur, Malaysia, with the ultratoxic VX nerve agent.

South Korea and Malaysia have accused North Korea of being behind the killing. If that was the case, Kim removed a potential rival, reminded the entire world that he has chemical as well as nuclear weapons, and demonstrated to all that he’s willing to use them. And if he’s willing to use them against his own family, what’s stopping him from using them to kill complete strangers in the United States, Japan and South Korea?

In 1994, North Korea committed itself on paper to the Nuclear Non-Proliferation Treaty and the so-called Agreed Framework between Pyongyang and Washington, agreeing to replace its nuclear power infrastructure with light-water reactors that couldn’t be used to produce nuclear weapons. In exchange, President Bill Clinton’s administration agreed to deliver half a million tons of heavy oil each year. The purpose was to prevent North Korea from building nuclear weapons without going to war. It failed.

A Gallup poll released in September found that 58 percent of Americans favor military action against North Korea if diplomatic options continue to fail, including 37 percent of Democrats. The United States absolutely could mount a preventive war against North Korea and would certainly win. Let there be no doubt about that. Let there be no doubt also that the cost would amount to a textbook example of a Pyrrhic victory, where the price of victory would be so high that it would be indistinguishable from outright losing.

Millions could die in South Korea alone, mostly in and around Seoul. Hundreds of thousands could die in Japan, too, if Kim, in a fit of malicious pique, nuked the Japanese. There’s no telling how many would die on the northern side of the Korean border. That would depend, in part, on whether the United States used nuclear weapons. And we might as well write off most of the 30,000 American troops stationed near the DMZ as potentially lost right at the outset.

North Korea’s conventional military power is no match for that of the United States and South Korea, but the early hours of a war would be so spectacularly destructive that using nuclear weapons might be on the table. President Donald Trump has made serious threats twice already.

“North Korea best not make any more threats to the United States,” the president said in August in front of the news cameras. “They will be met with fire and fury like the world has never seen.”

He did it again in September. “The United States has great strength and patience,” he said in a prepared speech at the United Nations, “but if it is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea.”

Kim, for his part, called Trump a mentally deranged “dotard,” said the Korean War was back on, and was moving military assets into place to shoot down American planes over the Korean Peninsula — even if they don’t fly over his airspace.

We haven’t been this close to total war with North Korea since the 1950s. Blame President Trump’s bellicosity if you want, or blame Trump and Kim equally, but the truth is that we’d be in crisis mode now even if Hillary Clinton or Bernie Sanders had won the election last year. Between 1984 and 2014, North Korea tested 53 missiles. Since 2014, it has tested more than 100 more, an increase from an average of two per year to more than 30 per year since Kim Jong Un assumed power from his late father, Kim Jong Il.

It’s not America’s fault that we are where we are. It is, however, up to Americans to decide what to do about it.

But what to do? None other than Trump’s hyperbelligerent former chief strategist Steve Bannon seemed to take the nuclear option off the table earlier this year. “There is no military option,” he said to Robert Kuttner of the American Prospect magazine shortly before the president fired him. “Forget it. Until somebody solves the part of the equation that shows me that 10 million people in Seoul don’t die in the first 30 minutes from conventional weapons, I don’t know what you’re talking about, there’s no military solution here. … They got us.”

Indeed, they “got” us. But we’ve also “got” them. The United States can’t possibly lose a war with North Korea — not today, and not in the future, not even if we get nuked, and not even if we get nuked first. North Korea can wreak an unspeakable amount of havoc, but only at the price of total annihilation. We can choose Pyrrhic victory. Kim can only choose suicide.

Blame Trump and Kim equally, but the truth is we’d be in crisis mode now even if Hillary Clinton or Bernie Sanders had won the election.

He doesn’t want to kill himself and his country. He is not a suicide bomber. ISIS “caliph” Abu Bakr al-Baghdadi in all likelihood would ignite an apocalyptic war if he could, but Kim just wants to survive and lord it over his totalitarian prison-state until he dies in his bed at the age of 90. And therein lies the least terrible option in a range of terrible options.

There is only one thing in the entire world that the North Korean and American peoples and governments agree on. We all want to survive, and to do so without perpetual angst.

Contrary to what most Americans believe, the Korean War never officially ended. It merely paused in 1953 with an armistice agreement. From the American point of view, the war has been over since before most of us were born. From the Korean point of view, though, it always has been a pyre doused with gasoline, awaiting a match.

The Korean War was fought far from our shores, but it was fought inside Korea, often in the backyards of those old enough to remember it. Most citizens of the North have been living with a feeling of existential dread that Americans could surge over the horizon at any moment and resume the bombing and killing. They have been brainwashed to believe this. The regime has spent decades unifying its people with a diet of deranged anti-American, anti-Japanese and anti-Seoul propaganda. It’s not just a big put-on, however. The Kim family watched as Americans demolished the Taliban regime in Afghanistan, Saddam Hussein’s Arab Socialist Baath Party in Iraq, and Muammar Gaddafi’s lunacracy in Libya. North Korea’s people feel, deep in their bones, that they might be “next,” just as Syria’s Bashar al-Assad did before the Russians flew in to save him.

They are almost certainly wrong about this. A war with North Korea would be so utterly devastating that there’s virtually no chance any American president would mount an Iraq-style regime-change operation in Pyongyang, even if Kim had no nuclear or chemical weapons, unless he invaded South Korea or hit us with missiles. The United States and its allies in Asia already are completely deterred by the thousands of artillery pieces pointed at Seoul.

Kim doesn’t need nukes. He just doesn’t know it or doesn’t believe it. The Mexican standoff between him and Donald Trump isn’t doing anything to settle his nerves.

Kim has erected a doomsday machine, and there’s no way we can destroy it without setting it off. Washington needs to think and behave like a hostage negotiator, which starts by managing and calming the emotional state of the hostage-taker.

The least terrible choice out of a range of terrible choices isn’t regime-change, which would set off Kim’s doomsday device; nor is it brinkmanship and gunboat diplomacy, which could inadvertently convince him that we’re coming for him and frighten him into setting it off prematurely. The least terrible choice is negotiating an end to the Korean War once and for all and guaranteeing the survival of his regime in perpetuity. Nobody who cares a whit about human rights wants to underwrite the indefinite existence of a totalitarian gulag state, but we’re not going to shoot Kim out of his palace anyway unless he starts a war. So, at the end of the day, what difference does it make?

Don’t count on the Chinese to save us. Yes, they can pressure Kim to the negotiating table, but the notion that Beijing can convince him to give up the nuclear weapons and missiles he already has is a fantasy. North Korea won’t give up its nukes for the exact same reason the United States won’t — there is no better deterrent on Earth. Even if Kim were to hand over or destroy the weapons he already has, his regime already has acquired the knowledge to build them and can always build more at any time. There is no rewind button, and toothpaste doesn’t go back in the tube.

Pressuring Pyongyang with threats of war and economic sanctions always had to be part of the picture. Kim would have far less incentive to negotiate if he did not feel compelled. But cooler heads need to prevail here, and sooner rather than later. The odds that Kim and his circle will be the first to act like the adults in the room are vanishingly close to zero. That’s our job, and Washington needs to snap to it.

Michael J. Totten is a contributing editor at World Affairs and City Journal, a Middle East Forum writing fellow, and the author of eight books, including “Tower of the Sun” and “Where the West Ends.”