WASHINGTON — The most powerful office in the world is occupied — and being abused — by a man who is entirely unfit and is spinning dangerously out of control. Everyone needs to stop pretending otherwise.

And it's all getting worse.

President Trump's train wreck of a performance Wednesday, at a meeting with congressional leaders, represented a new low on a scale that seems to have no bottom. "I pray for the president all the time ... I think now, we have to pray for his health," House Speaker Nancy Pelosi said later, because "this was a very serious meltdown on the part of the president."

Trump began by complaining about having to attend a meeting initiated by his own White House aides, according to published accounts. The subject was Trump's sudden decision to move U.S. military personnel in Syria aside, allowing Turkish troops and affiliated militias to sweep across the border and attack the Kurds, who had been loyal U.S. allies.

Trump then tried to make the case that he did not actually condone the Turkish invasion. Attendees were given copies of a truly bizarre and alarming letter Trump had sent to Turkish President Recep Tayyip Erdogan on Oct. 9. Just four short paragraphs long, the letter begins, "Let's work out a good deal!" It ends by telling Erdogan, "History will look upon you favorably if you get this done the right and humane way. It will look upon you forever as the devil if good things don't happen. Don't be a tough guy. Don't be a fool! I will call you later."

That is how the president of the United States communicated with a powerful foreign leader at a moment of crisis. We have all witnessed more sophisticated attempts at persuasion on kindergarten playgrounds. Erdogan reportedly threw the letter in the trash.

At the White House meeting, Trump went on to denigrate James Mattis, the decorated and highly esteemed Marine Corps general who served as Trump's defense secretary before resigning last year over Syria policy. Mattis is "the world's most overrated general," Trump announced, according to The New York Times. "You know why? He wasn't tough enough. I captured ISIS. Mattis said it would take two years. I captured them in one month."

Anyone in touch with reality knows that none of this is true. The territory held by ISIS — the Islamic State — was reclaimed by Kurdish fighters with the aid and guidance of U.S. troops and intelligence operatives. Shortly before the meeting, the House voted 354-60 to condemn Trump’s abandonment of the Kurds, with most Republicans joining their Democratic colleagues in expressing outrage.

Perhaps that vote was what set Trump off. "You're just a politician," he told Pelosi. Then he amended his assessment: "You're not a politician, you're a third-rate politician."

That's what Senate Minority Leader Chuck Schumer of New York heard; Pelosi thought she heard him say "third-grade politician." In any event, she and House Majority Leader Steny Hoyer rose to their feet and walked out.

They pressed Trump and his aides to explain what the plan was for fighting the Islamic State now that the Kurdish firewall is gone. They didn't get an answer because there is no plan. The president doesn't have the foggiest idea what he is doing.

Trump is in so far over his head that he doesn’t know which way is up. He also is intellectually, psychologically and morally unsuitable for the high office he holds. Those two problems -- incompetence and unfitness — reinforce each other, in the worst possible way, and have sent the presidency into a tailspin that puts the nation and the world in mounting peril.

Impeachment is no longer optional, given what we already know about Trump’s dealings with Ukraine. But the prospect of facing a Senate trial — for which Majority Leader Mitch McConnell is already making plans — can only boost Trump’s anxiety. His outbursts and tweetstorms are becoming more frequent and less tethered to the world of facts, events and consequences. Madness is a term laypeople use, not doctors. We must use it now.

I once was confident that our institutions and processes were durable enough to easily survive Trump. Now, I’m less sure. “Don’t be a tough guy. Don’t be a fool!” — a letter saying these things, on behalf of the United States government, was actually sent to the government of Turkey. Good lord.

Senators, pay attention. You may prefer to let voters judge Trump in next year's election. But you must realize, at this point, that we may not have that long.

Eugene Robinson’s email address is eugenerobinson@washpost.com.

© 2019 Washington Post Writers Group