They’ve tried. His people have tried to prep him for the meeting with Putin, and to convey to him the things he shouldn’t do. But does that mean he is prepared? Of course not. He doesn’t listen, he doesn’t remember, he doesn’t care, he doesn’t think anyone knows better than he does.

President Trump has been briefed repeatedly. His advisers have alerted him to the web of potential risks, complex issues and diplomatic snags.

But even his top aides do not know precisely what Mr. Trump will decide to say or do when he meets President Vladimir V. Putin of Russia face-to-face this week on the sidelines of the Group of 20 economic summit gathering in Hamburg, Germany. And that is what most worries his advisers and officials across his administration as he embarks Wednesday on his second foreign trip, first to Warsaw and then to Hamburg.

Of course it is. He has no impulse-control and no ability to think ahead. He’s like a clown on a spring.

“There’s a fair amount of nervousness in the White House and at the State Department about this meeting and how they manage it because they see a lot of potential risks,” said Steven Pifer, a former ambassador to Ukraine who has worked for the National Security Council and the State Department.

Mind you, that’s still a small amount of worry overall, because the State Department is so understaffed.

Mr. Trump himself is not troubled by the meeting. He has told aides he is more annoyed by the prospect of being scolded by the German chancellor, Angela Merkel, and other leaders for pulling out of the Paris climate accords and for his hard line on immigration.

What I’m saying. He’s too stupid to understand what he should be troubled about, and too narcissistic to tolerate the knowledge that Angela Merkel thinks he’s an ignorant buffoon.

A day before Mr. Trump was to leave Washington, the White House announced that the meeting with Mr. Putin would be a formal bilateral discussion, rather than a quick pull-aside at the economic summit meeting that some had expected.

The format benefits both. Mr. Putin, a canny one-on-one operator who once brought a Labrador to a meeting with Ms. Merkel because he knew she was afraid of dogs, will be able to take the measure of Mr. Trump.

So Putin will bring an intelligent woman to his meeting with Trump.

Mr. Trump’s aides are seeking structure and predictability. They hope that a formal meeting, with aides present and an agenda, will leave less room for improvisation and relegate Russia’s meddling in the campaign to a secondary topic, behind more pressing policy concerns that the president is eager to address.

“Nobody has found the slightest evidence of collusion, any evidence the vote was tampered with, so now they have turned their obsession to Russian ‘interference,’” said Kellyanne Conway, the president’s senior counselor and former campaign manager. “I don’t think that’s what the American people are interested in.”

And that’s how much Trump’s people care about the integrity of US elections – not at all.

The potential pitfalls are more than theoretical. White House officials recall with dread the images that emerged from Mr. Trump’s May meeting with Foreign Minister Sergey V. Lavrov and Ambassador Sergey I. Kislyak of Russia in the Oval Office, which showed the president grinning, laughing and clasping hands with the Russian officials.

The biggest concern, people who have spoken recently with members of his team said, is that Mr. Trump, in trying to forge a rapport, appears to be unwittingly siding with Mr. Putin. Like Mr. Trump, Mr. Putin has expressed disdain for the news media, and he asserted in a recent interview that secretive elements within the United States government were working against the president’s agenda. Two people close to Mr. Trump said they expected the men to bond over their disdain for “fake news.”

Well that’s Trump. Who exactly is it that they think they’re working for?