Ever since the Cold War’s end, the government of the United States has done its best to pretend that the government of North Korea does not exist. And again and again, Pyongyang’s leaders have reminded Washington that, unfortunately, it does. The most recent reminder came in February, when North Korea conducted its third nuclear test. Since then, leader Kim Jong-un has scrapped his country’s 1953 armistice with South Korea and threatened the United States so graphically that even Fidel Castro has pleaded with his Marxist brethren not to blow up the planet. The Obama administration, for its part, has sent warplanes and ships to the region, called for economic pressure, and pursued diplomacy—all of which stand a decent chance of defusing the current row and virtually no chance of ensuring that such rows do not return whenever the North Korean regime so chooses.

The bald truth is this: the relationship between the United States and North Korea will not fundamentally change until North Korea fundamentally changes. And once North Korea fundamentally changes and its Stalinist regime begins to cede power, reform will probably spiral into revolution, revolution will spur unification with the South, and in all likelihood, North Korea will cease to exist. Thank God.

All of which means that while the Obama administration is focused right now on preventing nuclear Armageddon, its broader North Korea strategy must be to do whatever it can, short of war, to hasten North Korea’s end. And the best way to do that would be to pledge formally that America will never station troops on what is now North Korean soil.

Here’s why. The only country with any influence over North Korea is China, which since the collapse of the Soviet bloc has been Pyongyang’s only important ally. According to the Council on Foreign Relations, China provides 90 percent of North Korea’s energy and 80 percent of its consumer goods and ensures that its military stays fed. China is clearly frustrated with its destitute, bellicose neighbor. In February, The New York Times reported that Chinese public opinion has turned against the North. That same month, an influential Communist Party editor argued that “China should consider abandoning North Korea” and “take the initiative to facilitate North Korea’s unification with South Korea.” In 2010, according to a WikiLeaks cable, South Korea’s vice foreign minister claimed that the Chinese leaders were increasingly sympathetic to a South Korean–led reunification of the peninsula.

But despite these hints of a potential shift in policy, Beijing keeps propping up Pyongyang. According to a February article in Foreign Policy by Fudan University’s Shen Dingli, there are three main reasons. The first is that China fears North Korea’s implosion could send tens or even hundreds of thousands of refugees fleeing across the two countries’ 800-mile-long border. The second is that North Korea’s collapse might prompt the millions of ethnic Koreans living on the Chinese side of the border to try to secede and join their kinsmen in a reunified Korea. The third is that if America’s ally South Korea swallows its northern twin, China could suddenly find itself with the U.S. military on its southeastern border.

There’s little the Obama administration can do to allay Beijing’s first two fears. But it can do a lot to allay the third. To realize how seriously China has historically taken the danger of U.S. troops in North Korea, one need only remember that when Douglas MacArthur’s men crossed the 38th parallel in October 1950, Mao Zedong and Zhou Enlai sent 200,000 Chinese troops to repel them. Sure, Sino-American relations have improved since then. But Beijing has watched unhappily in recent years as the United States “pivots” toward a containment strategy in which it bolsters military relations with as many of China’s neighbors as possible. Nor is it likely lost on China’s leaders that when Germany reunified in 1990, NATO troops soon deployed onto former East German soil.

Like the Soviet Union, which after World War II controlled Eastern Europe in order to guard against the threat of another invasion from the West, China has long desired what a 2008 United States Institute of Peace report called “a buffer zone” along its border. The best way to convince China’s leaders to cut North Korea loose is to reassure them that North Korea’s collapse won’t mean the end of that buffer zone, because it won’t mean American troops north of the 38th parallel.

That kind of reassurance isn’t simple. (Especially because Russian leaders believe that George H.W. Bush and James Baker reneged on promises not to expand NATO into Eastern Europe in 1990.) But the point is that the more the U.S. assuages China’s concerns about a reunified Korea, the more likely a reunified Korea becomes. Perhaps the best precedent is the way Ronald Reagan—who in his second term was the most dovish president of the Cold War, by far (if you disagree, read this)—dramatically reduced tensions with Mikhail Gorbachev and thus made it easier for the Soviet leader to loosen his grip on Eastern Europe.

The year 2013 isn’t 1987. In all likelihood, America and China will remain rivals, but preventing that rivalry from descending into cold war is crucial to toppling the most evil regime on the planet and sparing the world any more of its disgraceful nuclear bluster. Which would be nice right about now.