WASHINGTON — President Trump, having impetuously undone his historic meeting with North Korea’s Kim Jong Un, has hastened to put Humpty Dumpty back together again. He tweeted Friday: “Very good news to receive the warm and productive statement from North Korea” indicating it might agree to meet with him after all.

A North Korean spokesman said that “with a broad and open mind, we are willing to give the United States time and opportunity” to put the summit back on track.

Apparently, it didn’t take much for cooler heads in the administration like Secretary of Defense James Mattis to convince Trump to retreat, after attempting to pin the blame on Kim for killing the planned June 12 talks in Singapore, actually scuttled by the president’s own clumsy action.

His contorted letter to Kim, in which he buttered him up in classic Trump art-of-the-deal style, only underscored how it is unfit for serious high-level diplomacy, and the imperative need for grown-ups at the White House to save him from himself.

That requirement, provided this time around by former Marine Gen. Mattis, is distinctly not served by his new Secretary of State, the conservative former CIA Director Mike Pompeo, or his new national security adviser, the flame-throwing John Bolton.

The latter apparently provided the fuel for the Trump summit withdrawal with his toxic invoking of the so-called “Libya model” whereby the overthow and eventual assassination of dictator Muammar Gadhafi were achieved. Hapless Vice President Mike Pence mentioned it, giving Kim the grounds to draw his ire that triggered Trump’s pullout of the summit.

Mattis put the best possible face on his boss’s screw-up with his own undiplomatic remark that it all was only “a usual give and take of trying to put together big summits and stuff,” assuring reporters that “the diplomats are still at work” covering for Trump’s latest hip-shooting.

North Korean Vice Foreign Minister Kim Kye Gwan quickly joined in the fandango, saying, “We reiterate to the U.S. that we are willing to sit face to face at any time and in any way” to entertain a do-over.

But instead of moving forward with what at first was widely seen as a political coup for Trump, he must now try to proceed with egg on his face for revealing the price paid for a botched beginning by an American diplomatic amateur-hour team.

Once again, the president tried his best to shoe-horn into the discussion his standard partisan tweet, claiming, “Democrats are so obviously rooting against us in our negotiations with North Korea. … Dems have lost touch!”

What began as a possible major propaganda coup for Trump, to the point of premature chatter about a Nobel Peace Prize to him at a Michigan political rally, has reduced him to uncharacteristic crow-eating and slinking back to Square One in what for him is the totally unfamiliar territory of an equal playing field. Yet he continues to remind the North Koreans of American nuclear superiority that has never seemed to intimidate them.

Mattis on Friday held out hope that Trump’s misstep could be undone and that the June 12 date for the Singapore summit could yet be met. “If our diplomats can pull it off, (we) may have it back on, even,” he said. And the president added at the White House: “We’ll see what happens. We are talking to them now. It could even be on the 12th (of June). They very much want to do it. We’d like to do it.”

Kim has long been an enigma to U.S. policy experts. In this case, however, he may have met his match in Trump, not so much in the president’s inability to make up his mind but in his undisciplined inability to express it consistently from one day or even one minute to the next. Such is the state of global diplomacy in the age of The Donald.

Jules Witcover can be contacted at juleswitcover@comcast.net.