What did Donald Trump do today?

He packed a lot of nonsense into one tweet about North Korea.

Yesterday, North Korea completely broke off nuclear talks with the United States—although arguably it was never really in them in the first place. Trump, who has pointedly ignored North Korea's continued provocations over the last year and a half since he declared he had personally ended the nuclear threat, tweeted this today in response:

Kim Jong Un is too smart and has far too much to lose, everything actually, if he acts in a hostile way. He signed a strong Denuclearization Agreement with me in Singapore. He does not want to void his special relationship with the President of the United States or interfere........with the U.S. Presidential Election in November. North Korea, under the leadership of Kim Jong Un, has tremendous economic potential, but it must denuclearize as promised.

Almost every part of this is false, although Trump may actually have convinced himself that parts of it are true. Kim Jong-un signed an agreement last year in the Singapore summit he convinced Trump to give him, but he never agreed that "denuclearization" meant actually giving up North Korea's nuclear stockpile.

It's true that Kim's relationship with Trump is indeed "special," but not in a way that helps Trump. Since their Singapore meeting, Trump has turned a blind eye to smuggling and other sanctions violations, and shrugged off increasing and deliberately provocative missile tests aimed at demonstrating North Korea's ability to launch nuclear missiles at Japan. He also completely ignored a U.S. government report showing that the Kim regime was actively planning to hide its nuclear stockpile and deceive inspectors if the "talks" got that far. For his part, Trump has twice canceled joint U.S.-South Korea military exercises for fear that they upset Kim.

Trump's warning for Kim not to interfere in the 2020 election is a bit rich, since he openly declared this summer that foreign countries may do so. (In that context, of course, he meant it was all right for foreign interference to benefit him.) The kind of "interference" Trump seems to mean here is that North Korea would make him look bad by exposing how one-sided the "special relationship" is. Unfortunately for both Trump and the United States, there is nothing that can undo the political leverage Trump has given North Korea over himself.

Why should I care about this?

• The nuclear security of the United States is far too important for this level of incompetence from its president.

• A president who cares more about his political viability than dealing with nuclear threats is unfit for office.

• You are not a good dealmaker if, in your most important negotiations, you give up everything and get nothing, and then your opponent walks away.