One of the more bizarre spectacles of Donald Trump’s young presidency came on Saturday night, when he stood with Japanese Prime Minister Shinzo Abe at a press conference called after North Korea launched a ballistic missile into the Sea of Japan. Trump let Abe speak first, standing politely in the background as he condemned the test. When Trump took his turn, there was, uncharacteristically, no mention of inauguration crowd sizes, decrying of the media’s dishonesty, or settling of other political scores.

More importantly, he did not hype the threat of a North Korean missile hitting the United States. Seemingly eschewing longer prepared remarks, he offered two brief sentences: “Thank you very much Mr. Prime Minister. I just want everybody to understand and fully know, that the United States of America stands behind Japan, its great ally, 100 percent.” After three weeks of bungled executive orders and amateur phone calls with world leaders, Trump appeared almost, well, presidential.

On Sunday morning, White House adviser Stephen Miller said the Trump administration would “very soon” be sending a signal to North Korea, “a great rebuilding of the armed forces of the United States.” On Monday, Trump affirmed that he would deal “very strongly” with North Korea. Like Trump’s support of Japan, a muscular response could be a helpful message to America’s allies in the region. But that’s not the way to handle Pyongyang. Trump, in fact, had it right on Saturday. In addition to publicly and privately supporting Japan and South Korea, the best way to deal with North Korea, even when it cries out for international attention, is to publicly do nothing. That’s because North Korea is mostly China’s problem, not America’s.

The initial, panicked reaction to the launch, claimed by North Korean state media on Monday as a new nuclear-capable missile, overlooks one key fact: Pyongyang is unlikely to lob missiles or nuclear weapons at the United States. Experts disagree on how long it will be until North Korea possesses the technical capability to do so. Even if it does, Washington would likely be able to shoot the missiles down long before they reached America (or before they reached Japan or South Korea, for that matter). Unless the Kim Jong Un government commits regime suicide and declares war on South Korea or Japan, dragging the United States into a conflict on the Korean peninsula, it barely poses a military threat to America.  

The real threat, instead, is that North Korea will collapse, due to corruption, mismanagement, poverty, a military coup, or a populist revolt, or some combination of all five. That collapse would leave other countries—namely, China—to manage the chaos.

North Korea’s closest neighbor both geographically and psychologically, China has long been the Hermit Kingdom’s reluctant savior. In the early 1950s, Beijing sent more than 1 million troops to fight on the North’s side against the United States and South Korea in the Korean War. And since the fall of the Soviet Union in the early 1990s, the economic and food aid Beijing provides to the country have very likely proven decisive for the regime’s survival.

After all, if North Korea collapses, China would face the largest refugee crisis in its history, with thousands upon thousands of starving North Koreans fleeing across the two countries’ relatively porous border. Many would probably settle by the border, in China’s northeast, destabilizing an economically lagging region. A small number of these refugees might smuggle North Korean nuclear material or weapons through China—some of which could end up in the hands of disgruntled Chinese, who could use it to commit violence against the state.

North Korea’s collapse would also likely lead to the peninsula’s eventual unification under Seoul. This would not only put another Western-leaning democracy on China’s border, but could encourage the millions of ethnically Korean Chinese living in the country’s northeast to agitate for their territory to join a Greater Korea. Unlike the Tibetans, Uighurs, and even Mongolians, there is no independence movement among the Koreans: They don’t want to join the failed state of North Korea. But if the peninsula were a healthy, unified polity, this could change, giving China another unhappy minority population to manage.

The other major worry for China about Korean unification: the roughly 28,500 American troops stationed in South Korea. Many in China’s foreign-policy apparatus—and presumably some among China’s top leaders—fear that the United States treats China too much like the former Soviet Union. In other words, some in Beijing fear the United States is trying to contain China, and engender the collapse or the splintering of the ruling Chinese Communist Party. As a result, China does not want U.S. troops on its borders, which is exactly would happen if the peninsula unified. The United States has never credibly promised to remove those troops if the peninsula unified. And even if it did, Beijing may worry that Washington would break that promise, as some claim it did to Moscow with the expansion of NATO after the fall of the Soviet Union.

China’s strong preference that North Korea remain very much alive helps explain why it provides substantial aid to Kim Jong Un’s regime, and accounts for roughly 70 percent of his economy’s total trade. And this preference justifies Trump’s restraint when it comes to the missile launch. When he meets with China’s President Xi Jinping, rather than asking him for help in dealing with Kim Jong Un, it makes far more sense for him to let Xi ask for America’s help in negotiating with or curtailing his regime.

As for America’s allies who happen to be North Korea’s regional neighbors: Yes, North Korea’s standing army—estimated at more than 1.2 million—threatens South Korea, and Japan is a far easier target for its missiles than the United States. And yes, South Korea would face heavy casualties from a North Korean invasion. So, continuing to publicly and privately express support for those two allies is the smart way forward.

Trump is no paragon of self-control when it comes to realistically assessing the threats America faces. Far from it: He routinely exaggerates the dangers posed by Islamic terrorism and the Islamic State. But when it comes to North Korea, his reserve is laudable.