Updated on April 16 at 9:38 a.m. ET

Ahead of North Korea’s failed missile test over the weekend, Donald Trump vowed to “solve” the problem of Pyongyang’s rapidly developing nuclear-weapons program with or without China’s help, issuing that most Washington-y of warnings: “All options are on the table.”

The hazy declarations are a response to an ever-clearer threat, one that would arguably dwarf the danger posed by terrorism to U.S. national security. The North Korean government, which tested its first nuclear weapon in 2006, has dramatically expanded its trials of ballistic missiles and nuclear weapons in recent years under the leadership of Kim Jong Un. Less than two weeks ago, North Korea tested a missile that flew 37 miles before crashing into the sea, in contrast to this weekend’s test, in which the missile blew up almost immediately. Some experts estimate that North Korea could acquire the capability to hit the continental United States with a nuclear-armed long-range missile before the end of Trump’s first term. (The North may already be capable of staging nuclear attacks against Japan and South Korea.)


North Korea’s Escalating Nuclear and Missile Tests

Reuters / Center for Strategic and International Studies

Spend some time examining the North Korea table, however, and the options can seem dizzying. Proposed policies range from ramping up U.S. cyberattacks against North Korea’s missile program, as the Obama administration reportedly did in its final years, to ending U.S.-South Korean military exercises in exchange for North Korea suspending work on its nuclear program, as the Chinese have proposed. Other options could include sending American tactical nuclear weapons into South Korea or accepting a nuclear North Korea and devising ways to contain it.

I asked Victor Cha—a Korea expert who, as a Bush administration official, negotiated with North Koreans and witnessed it become a nuclear power—to walk me through the available options. His list was short. Ultimately, he said, there are only “two ways to impose significant costs” on the North Koreans for pursuing nuclear weapons. The United States “could use military power … or the Chinese can put real economic pressure on” North Korea. The first option could have horrific consequences, which is why so much rides on this week’s talks between Trump and Xi this week.

The Military Option

There’s a reason why Bill Clinton, George W. Bush, and Barack Obama all considered preemptive military strikes against North Korea’s nuclear sites and all eventually decided against it. (Clinton may have come closer than any other American president to ordering military action in 1994, when he nearly took out the nuclear reactor at Yongbyon.) As North Korea’s nuclear infrastructure has become more sophisticated, it has grown increasingly difficult to design a military campaign that could eliminate (as opposed to merely slow down) the entire program—especially now that the Kim regime has spread out its nuclear-weapons arsenal, facilities for enriching weapons-grade plutonium and uranium, and mobile systems for launching missiles. “It’s very hard to strike [these components] because you don’t know where they are,” Cha said.

North Korea could also retaliate against U.S. strikes by unleashing a barrage of artillery against the South Korean capital of Seoul, which is one of the largest cities in the world and roughly as far from the demilitarized zone separating the two countries as Washington, D.C., is from Baltimore. The North Korean military could place chemical weapons on that artillery. It could also target U.S. military bases in South Korea and Japan with ballistic missiles—potentially nuclear-tipped missiles. “It gets pretty ugly,” Cha said. There could “be millions of casualties if something like this were to happen.”

“It’s certainly true that dictatorships like North Korea—their primary goal is to survive,” Cha noted. “So could you carry out a strike against their nuclear facilities with a threat that if they retaliate we will wipe out the regime? Will a rational dictator then sort of sit still? Possibly. But that’s a big risk to take.”

The Economic Option

The Trump administration could mimic the Obama administration and patiently ratchet up international sanctions against North Korea as a way of pressuring it to return to negotiations over their nuclear program, Cha said. It could crack down on North Korea’s revenue from exporting slave labor to countries like China and Russia. But neither of those approaches will change one stubborn, significant fact: Roughly 85 percent of North Korea’s external trade is with China. And China has the ability to shut down that trade, ending barter trade along its border with North Korea and preventing North Koreans from using Chinese banks.

China, the world’s largest economy by some measures, “doesn’t need that trade,” Cha continued, and choking off its economic relations with North Korea is “the only thing that we can do at this point. It’s not going to solve the problem [of North Korea’s nuclear program], but if the North Korean leadership doesn’t have the money to buy Mercedes-Benz and cognac and all these other things, and if their bank accounts are being frozen in Chinese banks and elsewhere, they’re not going to be in a good position.”

As for the ultimate goal of placing North Korean leaders in such a bind, the “diplomatic answer is that that would then be a segue to negotiations in which everybody would be united [on] the terms for North Korea to freeze and then dismantle their program,” Cha explained. “The undiplomatic answer is that it puts enough pressure on the regime that there will be some sort of internal problems, and that Kim Jong Un might be challenged by others who see a better path for North Korea.”

I pointed out that the Chinese government’s fears about the collapse of the Kim regime—which could produce a refugee crisis, loose nukes, and an opening for the U.S. military to increase its presence on the Korean peninsula—are precisely why China has resisted applying economic pressure on North Korea for more than two decades. So why would they sign up for measures that could destabilize Kim Jong Un’s government?

Cha mentioned two developments that might make China more willing to cooperate with the United States than it has been in the past. First, “the Chinese are very worried” about mounting tensions between the U.S. and North Korea. “I think they feel like the situation is truly getting out of control. They have no political influence on North Korea, and I think they feel like they have no control over Trump.” Second, “Trump is unpredictable. We just don’t know what he’s going to do.” This is why Cha feels U.S. Secretary of State Rex Tillerson’s surprisingly terse statement on North Korea’s early-April ballistic-missile test—a statement that essentially declared, “I’m sick of talking about North Korea”—was effective. “People start paying attention because it’s not the typical U.S. response,” Cha said.

Cha experienced something similar in  2006, after North Korea conducted its first nuclear test. “President Bush said to [Chinese President] Hu Jintao at the time … ‘They just exploded a nuclear device in your backyard. If you don’t do something about this, I will.’ That’s not a direct quote, but [that was the essence] of it,” Cha recalled. “This was a president speaking who was in two wars, who had invaded two countries already. [The Chinese] were worried.” Nuclear talks with North Korea resumed, and the United States secured several (now-defunct) commitments from the North Koreans to roll back their program.

Cha said he expects the Trump administration to refuse to engage in nuclear negotiations with the Kim regime—negotiations the Chinese desire—until China reduces its trade with North Korea. He expects Trump to help establish missile-defense systems in South Korea and possibly Japan, a policy China opposes. And he interprets Trump’s pledge to solve the North Korean problem without China’s assistance if necessary as a veiled threat to impose so-called “secondary sanctions” on Chinese companies and individuals that do business with North Koreans, rather than a prelude to war.

“I prefer to not think of [a nuclear-armed North Korea] as a geopolitical reality,” Cha said. “The geopolitical reality is that this regime can’t last forever.” Of course: North Korea’s nuclear-weapons program is advancing by the day, and the Kims have clung to power for 69 years. For now, North Korean nukes and the Kim regime’s resilience are very much realities that the Trump administration must confront.