President-elect Donald Trump sounds certain about one thing. After North Korean leader Kim Jong Un declared on New Year’s Day that his country was on the verge of testing an intercontinental ballistic missile capable of reaching the United States, Mr. Trump tweeted, “It won’t happen!”

In fact, it will happen — unless a Trump administration radically rethinks U.S. policy toward the North.

The most generous interpretation of Mr. Trump’s bluster is that he doesn’t believe North Korea will be able to develop a functioning, nuclear-tipped ICBM. Such faith is unwarranted. To the surprise of foreign observers, the North in recent years has steadily and successfully conducted a series of nuclear and ballistic missile tests. Most experts believe that sometime within Mr. Trump’s first term, the U.S. intelligence community will notify him that North Korea has successfully tested an ICBM and will in the near future deploy a significant ballistic-missile force capable of striking the continental United States. This would make North Korea the world’s third hostile or potentially hostile country, with China and Russia, capable of wiping out San Francisco.

The other way to interpret Mr. Trump’s comment is as a threat, a pledge to stop any progress toward a working ICBM. None of the current strategies for doing so, however, is going to work.

Mr. Trump himself seems to believe that China “can strangle” North Korea easily. Yet it’s clear now that China will never put enough pressure on the North to halt its weapons programs. This shouldn’t come as a surprise. During my frequent trips to Beijing, Chinese experts and diplomats never tired of reminding me that, while China strongly dislikes North Korea’s nuclear adventurism, it prefers the status quo to all other alternatives — and won’t take steps that might destabilize the North.

Threatening China on other fronts — on Taiwan, say, or trade — is likely only to increase resistance in Beijing. Even so-called secondary sanctions that target Chinese banks and companies doing business with the North are unlikely to be effective. Chinese leaders have many ways to respond to such pressure — for instance, by establishing a separate bank to deal exclusively with North Korea, as they did to get around sanctions against Iran.

Indeed, given the prospects for a swift deterioration in U.S.-China ties under President Trump, it’s more likely that China will weaken rather than enforce existing sanctions against the North. Because China accounts for more than 90 percent of North Korea’s foreign trade, that would virtually guarantee their failure.

It’s also important that the market-oriented reforms initiated by Mr. Kim are working. According to international estimates, the 2016 harvest was up 7 percent from 2015; rice production increased an impressive 23 percent. The North Korean economy, driven by an unofficially tolerated private sector, is growing at close to 3 to 4 percent. Remarkably, this recovery began soon after the sanctions were introduced — further proof of their ineffectiveness.

This reality has, in certain circles, revived the once-taboo idea of a preemptive strike to take out North Korea’s nuclear program. Yet, while an air-and-missile campaign might set the North Korean program back a few years, the North would almost certainly retaliate by devastating Seoul, home to 24 million people, with thousands of rockets. Such a strike also would likely destroy the U.S-Korea alliance. Many South Koreans would view preemptive American action as criminally selfish — addressing a distant threat to the United States at the cost of creating an immediate threat to South Korea.

Finally, some observers seem to hold out hope that Mr. Trump, a self-described “great” dealmaker, might be able to talk Mr. Kim out of his nukes. This, too, would be futile. U.S. and North Korean interests are fundamentally incompatible. North Korean leaders fear that giving up their nukes would leave them dangerously vulnerable; they well remember what happened to Moammar Gadhafi after he negotiated away his nuclear program.

The truth is that, for more than a decade, there’s been no real chance of fully eliminating the North’s nuclear program. Even now, though, the United States might be able to negotiate something better than the current situation: a verifiable freeze on nuclear and missile testing, before North Korea develops an ICBM.

Of course, Mr. Kim isn’t going to restrain himself for free. He will demand many things — a hefty aid package, above all, but also political concessions, including a formal peace treaty. No doubt his regime will probably try to cheat.

The opponents of such a compromise will describe it as a terrible precedent, even blackmail — and they may be right. Unlike Iran, North Korea would remain a nuclear power even after signing such a deal. But the alternatives — either a major war that drags in the United States and China or a fully armed North with the proven capacity to attack the U.S. mainland — are worse. As long as there’s still a chance of striking such a compromise, the incoming president should be doing everything he can to seize it.

Andrei Lankov is a professor of history at Kookmin University in Seoul and the author of “The Real North Korea: Life and Politics in the Failed Stalinist Utopia.” He wrote this for Bloomberg View.

First Published: January 19, 2017, 5:00 a.m.