Over the past half century, the United States has fought only one big war—in Kuwait, in 1991—that was a conventional conflict. Operation Desert Storm launched a U.S.-led coalition against the Iraqi Army after it occupied oil-rich Kuwait. The combat was quick (six weeks) and successful in its limited goal: expelling Saddam Hussein’s forces from the small Gulf sheikhdom. Fewer than a hundred and fifty Americans died in battle.
America’s other big wars over the same period—in Vietnam, in the nineteen-sixties and seventies; Afghanistan, after 9/11; and Iraq, on and off since 2003—have been unconventional. They pitted a well-trained army with the world’s deadliest weapons against insurgents, militias, terrorists, or a poorly trained army, all with far less firepower and no airpower. In each, asymmetric conflicts stymied the United States. Wars dragged on for years. Death tolls were in the thousands—in Vietnam, tens of thousands. The aftermath—and unintended consequences—were far messier and bloodier. The price tags were in the trillions of dollars.
A war with North Korea would probably be a combination of both types of conflict, played out in phases, according to former generals who served in Korea and military specialists. The first phase, they say, would be a conventional war pitting North Korea against American and South Korean forces. It could start several ways, but two scenarios, both preëmptive actions, reflect how a full-fledged conflict might start—even if unwanted by both sides. Asked on Wednesday if he was considering military action, President Trump told reporters, “Frankly, that’s not a first choice, but we will see what happens.”
In the first scenario, the United States could engage in what is known as a left-of-launch strike just before a North Korean missile liftoff, or in the first seconds of its flight. This could be done kinetically or by cyberattack, although it’s unclear whether the United States has that full cyber capability yet. The regime of Kim Jong Un has already launched eighteen missile tests this year. South Korea reported this week that Pyongyang may test another intercontinental ballistic missile within days. If the Trump Administration chose to thwart a missile test now or in the future, former generals and military analysts told me, North Korea is likely to retaliate, possibly escalating tensions into open warfare and unleashing weaponry Pyongyang feared it might otherwise lose in U.S. air strikes.
The second possible scenario would be North Korea initiating military action because of fears or signals that the United States is close to an attack. The signals could range from small steps, such as Washington pulling out diplomatic dependents from South Korea, to major actions, such as deploying more military aircraft, equipment, personnel, or even nuclear weapons in the South. Pyongyang could preëmptively attack to fend off what it feared was going to be a full-scale invasion.
Fiery rhetoric from both sides has escalated tensions over the past month. In August, President Trump vowed, “North Korea best not make any more threats to the United States. They will be met with fire and fury like the world has never seen.” A few hours later, the Strategic Force of the North Korean People’s Army countered, “It is a daydream for the U.S. to think that its mainland is an invulnerable Heavenly kingdom.” The incendiary rhetoric is sucking the air out of diplomacy, a track still heavily favored by South Korea, China, Russia, Japan, and Europe. As a result, brokering any compromise on Pyongyang’s nuclear reality seems more distant, especially given its rapid pace of weapons and delivery-system development, exceeding all intelligence estimates. The only deal Kim might now consider is a freeze—and at a heavy price from the West, which the White House seems unwilling to negotiate, or even talk about what else would be acceptable.
If war erupted, the first phase would likely play out for at least a month, and possibly many weeks more. “North Korea is in a position now where its conventional warfare has atrophied over the years and not been modernized much,” the retired General Gary E. Luck, the former commander of both U.S. and U.N. forces in Korea, told me. “But it still has the numbers in its military—because of the type of regime it is—that it could execute a conventional war not far afield from the last time around.” It also now has a nuclear bomb.
North Korea has almost 1.2 million troops in its various military branches, plus another six hundred thousand in its reserves and almost six million in its paramilitary reserves, according to “Military Balance 2017,” published by the International Institute for Strategic Studies, a global think tank. South Korea’s armed forces are about half the size of the North’s, but it has 4.5 million troops in its reserves and another three million in its paramilitary reserves. Partly because there is still no formal end to the last Korean War, only an armistice, the United States has about twenty-eight thousand troops deployed in South Korea, with tens of thousands more in the U.S. Pacific Command.
In the end, North Korea would lose a war, the generals and military analysts say. The regime of Kim Jong Un would probably collapse.
But the Second Korean War could be deadly—producing tens of thousands of deaths just in Seoul, and possibly a million casualties in the South alone. It would almost certainly be devastating physically in both the North and South, military experts say.
“The devastation to the peninsula would be disastrous, just disastrous,” the retired Major General James (Spider) Marks, who served in both Korea and Iraq, told me. (During the first Korean War, between 1950 and 1953, the United States lost more than thirty thousand troops in battle. South Korea lost almost a quarter million troops and a million civilians. In North Korea, just over a million troops and civilians are estimated to have died.)
Luck, a Purple Heart recipient who served in Vietnam and the first war against Iraq, told me “it would be a very tough fight.” He said, “in the end, we would win, but the price we’d pay to get there would be pretty dadgum high. There would be horrendous loss of life. There are twenty-five million people in South Korea within artillery range of North Korea.” North Korea has thousands of artillery pieces embedded deep in the northern slopes above the Demilitarized Zone that divides the Korean Peninsula.
Lost in tensions over North Korea’s nuclear programs are its chemical and biological weapons, Luck added. “They are something to be worried about.”
As bad as the scenario for the first phase seems, the second phase could then get worse. “A war would not end quickly after the defeat of North Korean forces,” Mark Fitzpatrick, the executive director of the International Institute for Strategic Studies office in Washington, told me. “North Korea would not be immediately pacified.”
A conventional conflict could then devolve into the now familiar kind of insurgency that U.S. forces face in the Middle East and South Asia. Loyalists to the Kim regime might fight on in covert cells and costly guerrilla attacks.
“North Korea would not go down as fast as Saddam’s regime (in less than a month of the U.S. invasion) or the Taliban (in two months), but the aftermath would be similar and probably of greater intensity,” Fitzpatrick said. “North Koreans are brainwashed into believing that the Kim dynasty is deity-like and Americans are the source of all evil.”
Numerous war games have analyzed what it would take to eliminate the regime and its weaponry, he noted, but little has been done to study what might happen afterward. The same problem plagued military interventions in Iraq and Afghanistan: they achieved their initial goals, only to get sucked into open-ended quagmire.
Marks, the retired general, compared U.S. vulnerabilities in Phase II to problems with nato’s planning for possible war with the former Soviet Union. “No plans extended into the phase of conflict following war and the likely use of nuclear weapons to stop the advancing Soviet ground forces,” he told me. “Unconventional war fits no pattern, defies the military planner’s imagination—and might obviate the use of force in the first place.”
One of the big unknowns is what China would do if war were to break out in the neighboring Korean Peninsula. Beijing does not want North Korea to have nuclear weapons. The latest U.N. resolution imposing new sanctions on Kim’s regime produced rare unanimity among the fifteen members of the Security Council. But China is also North Korea’s closest economic partner; its southern provinces are heavily involved in trade with Pyongyang. Beijing views North Korea as a buffer to prevent Western influence along its border. It does not want reunification of the peninsula. And it would shudder at the prospect of North Korea’s collapse and future instability on its border, the military analysts told me.
U.S. air strikes of some North Korean targets might require flying not far from the border with China, Marks warned. And China would be just as concerned as the United States would be if another country came that close to U.S. borders. “North Korea is a subset of our relations with China,” Marks told me. “What impact would a war have? Devastation of Seoul, the unravelling of world order, and China on the other side with ‘enemy’ status. And if the United States and China are belligerents, everything is up for grabs.”
The dire predictions about what a possible war with North Korea would look like are among the many reasons that current and former military officials strongly favor more diplomatic outreach—whatever President Trump says publicly. Last week, Trump tweeted, “The U.S. has been talking to North Korea, and paying them extortion money, for 25 years. Talking is not the answer!” Hours later, James Mattis, the Secretary of Defense and a former marine, publicly broke with the President. “We’re never out of diplomatic solutions,” Mattis told reporters while standing next to South Korea’s Defense Minister, Song Young-moo, at the Pentagon.
Marks told me that Mattis’s statements reflected the views of top American commanders. “There is certainly a hawkish option on North Korea,” he said, “but there is no hawkish faction at the Pentagon. Nobody wants another war in Korea.”