Presidents Donald Trump and Xi Jinping will meet at Mar-a-Lago April 6-7, with the Chinese trade surplus and the North Korean threat highest on the agenda. Which country should take the lead in dealing with Kim Jong-un’s regime is the more consequential by far.

Beijing, to everyone’s dismay, has refused to act decisively against the Kim Jong-un regime, to go beyond continued sanctions and rather aimless diplomacy. Trump, realizing that the North’s nuclear program is becoming a danger to the U.S. itself, now says Washington is ready to act unilaterally with military force if necessary. Whether this is another Trump empty threat remains to be seen but Pyongyang is certainly pushing its luck.

Two facts about North Korea’s threat must be kept in mind. The first is that Pyongyang has no genuine allies or friends, not even China. Second, the issue of which government should lead in dealing with Pyongyang is at a critical point.

Beijing is usually depicted as North Korea’s ally but this is not so. The Kim regime’s hermetic, pitiless, medieval-Stalinist state is a danger to China itself. In any conceivable military conflict, Beijing wouldn’t think of counting on North Korea’s military forces. As for friendship, solidarity among Communist parties died decades ago. And it makes little sense to think of the Kim regime as Communist in any case.

Beijing’s only strategic interest in the North is its location, meaning its value as a buffer state between China and South Korea. It’s not that South Korea itself is a military threat to China. South Korea worries Beijing because it is part of the overall United States sponsored security arrangements in East Asia, which China sees as attempted strategic encirclement. Under the U.S.-South Korean Mutual Defense Treaty of 1953, the U.S. guarantees South Korea’s security, with almost 30,000 U.S. military personnel stationed there as a tripwire against attack from outside. As far as China is concerned, South Korea represents the “West,” the liberal democratic world order in East Asia, of which Japan is the other major power. If the Kim regime collapsed and the Korean peninsula was unified under South Korea’s system, the result would be that the West would have arrived on China’s own borders.

The Kim Jong-un regime does however have one other value to China. It holds North Korean society afloat, even in the population’s wretched condition. If the Kim regime collapsed, China’s own stability would be affected if millions of North Korean refugees ran for the border.

For its part, the Kim regime needs Beijing merely to survive. China is North Korea’s only significant trading partner and in a sense a strategic guarantee because Beijing would be the first country, along with South Korea, to be affected by political destabilization or revolution in the north. This is why the Chinese want to avoid turning the screws down harder.

Beijing seems to have no North Korea policy beyond kicking the can down the road or else it’s been well hidden. What’s on the surface is that China wants somebody else to take the lead. This is either shrewd strategy or else a great loss of face. North Korea is China’s neighborhood.

The Beijing/Pyongyang relationship is poisonous. What could force China’s hand is some unexpected event in North Korean politics or some new initiative from outside the region.

Beijing has to play the game carefully with the North Koreans. If the Kim leadership believed the Chinese had decided actively to overthrow it, it would have the strongest incentive—survival itself—to use its massive conventional forces or its weapons of mass destruction against China.

There are nuclear weapons, although it’s not clear to what extent short or medium-range missiles are already deployed. We know Pyongyang still has no inter-continental delivery capability but they are moving rapidly to build one, thus in theory to threaten the American mainland. Everyone assumes the North’s missiles threaten South Korea, Japan and the U.S. but it’s hardly ever noticed that missiles can be pointed in all directions, for example toward China. But the Chinese must understand this very well.

Pyongyang also has chemical and biological weapons that bolster the power of its 1.2 million man conventional forces. (North Korea is known to have amassed thousands of tons of chemical agents.)

What is China’s thinking about a possible military conflict with North Korea? If such a situation somehow developed and North Korea attacked China with WMD, what would Beijing do in response? Would it use its nuclear weapons on North Korea? How could it not? The consequences would be incalculable. In other words, a North Korea/China war could quickly mount the escalation ladder.

Seen in this perspective, Pyongyang’s sensationalist threats against the U.S. are pure propaganda to fool its population. China, in the various plausible scenarios, is a more likely enemy than the U.S.

Thus the issue of Beijing’s reluctance to pressure North Korea more heavily is not basically Chinese bad faith. The Chinese like everyone else want to see the Kim regime gone. The intractable issue is simply that nuclear weapons are the Kim regime’s only method of survival and adversaries must presume they would be used. The Kim regime has turned itself into a genuine menace of incalculable regional destruction.

Given all this, there are two plausible strategies. The first is “strategic patience,” which is a version of containment strategy. It means living with North Korea’s expanding nuclear program for years or even decades, banking on peaceful evolution inside Pyongyang’s leadership and acceptance of North Korea as a permanent nuclear state. But strategic patience was not only the Obama administration’s policy. Without saying as much, it’s the policy of all concerned states. The historical caution in this approach is that no government having developed a full-scale nuclear deterrent has ever abandoned it. (Ukraine’s missiles were Soviet property, not its own.)

The second strategy is a coup d’état that eliminates Kim Jong-un and his clique. It could be organized entirely from within by “moderates” who want to return to international civilized existence, probably helped by outside governments including the U.S., China, South Korea and Japan. Outside military forces would arrive quickly in the country to secure all the weapons of mass destruction, nuclear, chemical and biological. The best result would be an immediate offer by the leaders of a new Pyongyang regime to give up all its WMD.

On the other hand, both of these strategies are high-risk and it’s not even clear which is the less dangerous, long-term containment or regime change.

Presidents Trump and Xi at Mar-a-Lago should discuss which government has first responsibility for dealing with the North Korean threat. All the relevant states seem to assume that the U.S. must take the lead. Why?

U.S. leadership makes sense with respect to South Korea and Japan but what about China? American commentators usually say vaguely that the U.S. ‘needs China’s help’ with North Korea. But why should the U.S. necessarily take the lead, especially when it’s not the most immediately threatened country? And what does ‘taking the lead’ actually mean? Organizing long-term containment, or preparing a coup and/or an air-ground attack involving America military forces?

Why shouldn’t China take the lead? Shouldn’t the Xi Jinping leadership want to take the lead if it now seeks international influence and a ‘new major power relationship’ with the U.S.? Why, as candidate Trump said during the campaign last year, is it always the Americans who must take the lead and run the risks? Would it in fact be in the U.S. national interest to ask or goad Beijing into taking the lead?

These are no longer merely rhetorical questions. President Trump and his national security advisors need to get further along in strategic thinking about North Korea than the Obama administration.

There’s a large possibility here. Dealing with North Korea could be the occasion for an unprecedented security agreement in East Asia as a whole. Serious conflicts oppose China, South Korea and Japan. But, in dealing with North Korea, common national interests of the highest importance unite them, whatever else divides them, whether conflicts in the China Sea or trade or elsewhere. Even, one might posit, historical enmities.

The two presidents could launch a wide-ranging international success if they emerged from their meetings with a common policy vis-à-vis the Kim regime.