Why ‘5027’ is a number you should know: How war in Korea might unfold

Next month, this column will be moving to another platform. But before we go, in celebration of eight happy and productive years at Foreign Policy, here are the most popular items ever to run on the Best Defense. This item, which originally ran on May 1, 2017, is number 9. 

If there is one problem the U.S. military has studied and thought about, it is war on the Korean peninsula. The U.S. Army’s heart may still reside in Germany’s Fulda Gap, but the Army has been in Korea for almost as long as it has been in Germany. And the other services, especially the Navy, had little role in that scenario.

By contrast, all our armed forces, including the Air Force, a military service too rarely mentioned in this blog, have thought long and hard about what their roles might be in going into North Korea. There’s almost a comfort in thinking about it, compared to dealing with newfangled tangles like Syria and Yemen. The Marines can think about amphibious landings. The Navy can sail around three sides of Korea, which is convenient, especially for putting out Aegis destroyers that can knock down missiles, especially in their vulnerable, fuel-laden boost phase. And the fifth service, Special Ops, would have dozens of spectacular missions to carry out on the ground, going after launch sites, communications, and command-and-control bunkers.

How would Korea turning hot unfold? U.S. military planners have thought about this for decades, especially over the last 20 years as North Korea has sought to develop a nuclear weapon and long-range missiles capable of carrying such a warhead. Indeed, there are multiple “Operations Plans,” and I remember being given quiet briefings on some of them.

OPLAN 5027 had the U.S. military deploying to the theater of war over about 90 days hundreds of thousands of troops, plus half the U.S. Navy and over 1,000 aircrafts. There’s also OPLAN 5029, for dealing with a sudden collapse of the Pyongyang government and doing things like securing nuclear and biological weapons stocks. Each of these plans have had multiple iterations as commanders have come and gone, and also as global circumstances have changed.

But there are some big and difficult questions.

First, there is the problem of a preemptive strike. Could the U.S. military conduct airstrikes that blow up the missiles and warheads? No. Those almost certainly are tucked away in tunnels carved away deep into hard rock. (The North Koreans are big on tunneling. I was once in a the southern end of a tunnel they dug under the DMZ. It was impressive, and it was said to be just one of many. On the same foggy day, our Army UH-60 helicopter pilot, flying north from the capital, got lost and so landed the aircraft at a U.S. outpost just short of the DMZ. Red-faced, he glumly informed us that there are two types of helicopter pilots: Those who get lost, and those who falsely claim they don’t.)

But U.S. airstrikes, launched from bases in the South, or from Japan, or even Guam, combined with heavy jamming and cyber ops, could probably severely degrade North Korea’s ability to launch anything. Their internal communications would almost stop. And if you are going preemptive, there’s a good chance you are going to conduct a decapitation strike aimed at destroying Pyongyang’s ruling elites. Drones could loiter overhead to provide warning of any launcher rolling out of a tunnel. Being a North Korean launcher operator would become the world’s most hazardous job, but with plenty of opportunity to move up the ladder.

Here’s the first big problem with preemption: North Korean artillery. They have a lot — I mean, thousands — of artillery pieces along the DMZ. And the moment they got a whiff of what was going on, they’d probably start firing shells into Seoul. I don’t think they could keep it up for long — the tubes are probably shoddy, they’d have a lot of duds, and they’d find that keeping them firing is hard when the other side is firing back and probably cluster bombing every tunnel door that opens. The prospect of artillery shells landing around the greater Seoul area, with a population of over 20 million, is grim, even if the shelling can’t reach the southern part of the city, and even if it lasts only a few days. But it still wouldn’t be the “sea of fire” that Pyongyang a few years ago promised to rain down on Seoul.

And then there’s the Pottery Barn problem: The more you remove the Kim family monarchy in the North, the more you own the problem — and are responsible for, among other things, feeding and policing the population. Even if you can persuade the UN to put in peacekeepers, the United States is going to have to provide the logistics — few other nations are capable of doing even a fraction of it. There almost certainly would be major humanitarian relief operation, at the very least.