Washington — With the abrupt breakdown of the Hanoi summit, the diplomatic negotiations between the United States and North Korea got a reset, and that’s a good thing. If dialogue resumes, it will be on a firmer, more realistic basis.

President Trump’s swoon for North Korean leader Kim Jong Un had worried many observers who feared the president would make a rushed, overly generous deal just to claim a win. Cautioned by Secretary of State Mike Pompeo to avoid concessions on sanctions before he had hard evidence that North Korea was truly moving toward full denuclearization, Trump decided that “sometimes you have to walk.”

After the summit collapsed Thursday without an agreement, some commentators blamed Trump for lack of preparation. This president doesn’t prepare very well for anything but, in this case, the criticism is somewhat misplaced. It was the North Koreans who blocked adequate groundwork, by resisting U.S. efforts to plan for a productive meeting.

North Korea’s foot-dragging has been obvious in public comments. When Pompeo visited Pyongyang in July, a month after the first Trump-Kim summit, to frame a serious agenda for delivering on the Singapore framework, the North Koreans denounced his “unilateral and gangster-like demand for denuclearization.” Through the summer and fall, the United States kept pressing for working-level talks between special envoy Stephen Biegun and his counterpart in Pyongyang, but the North Koreans resisted. When talks finally commenced, the positions were too far apart, with too little time for negotiation and compromise.

Kim may have been encouraged to delay working-level negotiations by Trump’s gushy praise and the president’s emphasis on his personal chemistry with the young dictator. But the failure of the Hanoi summit will hopefully cure each side of any illusions about sweet-talking the other.

The failure in Hanoi now puts both parties in closer touch with reality. Pompeo and Biegun — determined to avoid the failure of past U.S. efforts to stop the North Korean nuclear program — have been adamant that U.N. sanctions shouldn’t be lifted unless North Korea takes steps to make its denuclearization pledges more believable. Pyongyang’s proposal in Hanoi to dismantle its Yongbyon nuclear complex failed that test, because other secret facilities would remain. North Korea now knows it will have to make a better offer.

Trump appears to have learned that he doesn’t have any magic diplomatic formula. He seemed convinced that his combination of saber-rattling disruption, punishing sanctions and diplomatic love letters would work, but, so far, it hasn’t (despite a laudable reduction in tensions).

The president may grow bored now, as he often does when he encounters a reversal. But if he’s serious about North Korea, he (or more properly, Pompeo and Biegun) should settle in for long, careful negotiations that, meeting by meeting, reduce the threat North Korea poses and open pathways for its development.

Walking away from engagement with North Korea would be a mistake. But hitting the pause button now makes some sense.

— David Ignatius is a columnist for Washington Post Writers Group.