WASHINGTON — When the establishment told him he should talk with North Korea, President Trump scorned the idea. “Presidents and their administrations have been talking to North Korea for 25 years” and had been made to look like “fools,” he scoffed, and then rattled his saber. “Sorry, but only one thing will work!”

Five months later, Mr. Trump cast aside his skepticism and agreed to talk to North Korea with no more promise of success at negotiating an end to its nuclear and missile programs than his predecessors had. The main difference this time around is who will do the talking for the United States: Donald J. Trump.

Shocking and yet somehow not surprising, Mr. Trump’s decision to do what no other sitting president has done and meet in person with a North Korean leader reflects an audacious and supremely self-confident approach to international affairs. Whether it is Middle East peace or trade agreements, Mr. Trump has repeatedly claimed that he can achieve what has eluded every other occupant of his office through the force of his own personality.

So far, he has little to show for that. He has yet to successfully negotiate any new trade deals or renegotiate any old ones. A resolution between Israel and the Palestinians, which he once said would be “maybe not as difficult as people have thought,” looks more distant than when he came into office. Beyond threatening “fire and fury,” he has offered no original formula that suggests a path to unlock the North Korea puzzle.