In such a scenario, the United States would have to address China’s long-term security concerns over the Korean peninsula. Beijing would almost certainly demand that Washington end its military alliance with Seoul and withdraw its troops from the peninsula. China may sweeten this deal by proposing that the United States work to jointly guarantee the security of a neutral unified Korea.

But given the strategic distrust between America and China and their great-power rivalry, it’s hard to imagine either government embracing this radical alternative. There is good reason why they have not yet engaged in official or semi-official discussion on the future of the Korean peninsula (no such meeting has ever been reported in the media, and my colleagues both in China and America know of no such discussions). In Beijing, a regime collapse in Pyongyang is a taboo subject the Chinese official media has never broached. At the same time, Washington would likely reject the idea that it should accommodate China’s security concerns and withdraw its forces after the reunification of the two Koreas (leaving aside whether a reunified Korea would want the U.S. troops to leave). An obvious concern of Washington’s is that an American exit from the Korean peninsula could perhaps fatally undermine the U.S.-led system of alliances in East Asia. Once the U.S.-Korea military alliance dissolves, Washington would be left with Japan as its sole treaty ally in northeast Asia.

With the alternatives appearing either infeasible or unthinkable, China is likely to stick with its current policy for the foreseeable future, despite the fact that this is unlikely to reverse the dangerous dynamics on the Korean peninsula. In the short term, the political turmoil in South Korea may give China a chance to complicate the life of the Trump administration. The impeachment of President Park Geun Hye has created an opening for South Korea’s leftists, who favor a softer line toward North Korea.

In the event that Moon Jae In, the leader of the opposition Minjoo Party, wins the special presidential election in May, China is expected to pursue two immediate priorities. First, it will push Seoul’s new government to back out of the THAAD deal with the United States. Second, it will throw its weight behind Moon’s more conciliatory approach to Pyongyang, thus raising the pressure on Washington to reengage Pyongyang diplomatically.

The combination of China’s continuation of its current policy and South Korea’s political uncertainty has made Secretary of State Rex Tillerson’s upcoming trip to the region a challenging task. In all likelihood, the most he can hope for is some non-committal reassurance from Chinese leaders about working with the United States. To be sure, the just-announced summit between Presidents Donald Trump and Xi Jinping in Mar-a-Lago in April should be welcomed as a positive indicator of potential improved U.S.-China cooperation on the Korean peninsula.

But we should also temper expectations. Unless the upcoming summit reaches a grand bargain that stabilizes U.S.-China relations across the board, the risks that the Trump administration will push back against China on trade and security will remain high and China will have little incentive to help America out where North Korea is concerned. If anything, the unfolding crisis in North Korea could get far more dangerous.

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