Donald Trump is finding out that tough talk doesn’t get you anywhere in the real world.

He tweeted in January, before taking office, that he would not allow North Korea to develop a nuclear weapon that could reach the United States.

As president, he pressured China to rein in the nuclear ambitions of its client state, threatening commercial reprisals if it didn’t.

Neither appears to have been impressed.

Missile test

North Korea successfully tested its first intercontinental ballistic missile (ICBM) on Tuesday, which it claimed could reach Alaska.

ICBMs are only useful for delivering nuclear weapons. If you want to drop a conventional bomb half a world away, it’s more efficient to use an airplane. That’s why the only countries with ICBMs are nuclear powers.

North Korea hasn’t quite crossed Trump’s red line. Joshua Pollack, an arms-control expert, points out that the communist state has yet to flight-test an ICBM while Quartz reports that the next step is making sure the weapons payload survives the heat and force of reentry.

South Korea’s defense minister, Han Min-goo, has said the recent test doesn’t provide enough evidence that the North has mastered this technology.

Setback

The missile test is nevertheless a setback for Trump, who thought he could browbeat the North Koreans into giving up their nuclear program or at least convince China to do it for him.

If the North Koreans are intimidated, they are making a good show of hiding it.

As for China, Trump himself admits it hasn’t ramped up the pressure on Pyongyang.

Its calculation hasn’t changed: It doesn’t want North Korea to become so reckless as to invite war, but it also doesn’t want the Kim regime to collapse and see Korea reunified on American terms.

The last three presidents have grappled with this dilemma. Neither Bill Clinton nor George W. Bush nor Barack Obama found a solution. What made Trump — who had zero diplomatic and political experience before running for president — think he could do better?