He has managed to alienate our closest allies — even drawing a rare rebuke this week from British Prime Minister Theresa May — and created a vacuum in world leadership that China is happily beginning to fill.
The logical thing to do, at this point, would be to come up with a new strategy. But Trump stays his wild and erratic course, as if he simply cannot help himself.
The most alarming development is the revelation that Trump continues to entertain paranoid conspiracy theories of the kind usually found beneath tinfoil hats.
According to both The Post and the New York Times, Trump still clings to the ridiculous "birther" theories about where former president Barack Obama was born.
The papers also reported that Trump has privately claimed the infamous "Access Hollywood" tape, in which he bragged about harassing and assaulting women, was somehow forged or doctored.
You will recall that Obama's birth in Hawaii has been definitively proved; and also that Trump acknowledged the "Access Hollywood" tape when it surfaced last year and gave a video address apologizing for it. "I said it, I was wrong, and I apologize," then-candidate Trump told the nation.
It would be one thing if Trump were broadcasting this nonsense for a reason. I'd feel better even if he had a nefarious reason — to appeal to racists who cannot accept the legitimacy of the first black president, say, or to encourage his base to doubt everything they see and hear in the media and instead to trust only him.
But Trump has raised these off-the-wall subjects in private conversations with aides, associates and a sitting U.S. senator — settings in which the president is likely to say what he truly believes.
It is one thing to create a fantasyland for political ends — appealing to some voting group's prejudices or giving supporters a reason to excuse bad behavior.
It is another thing altogether, however, for Trump to fall into his own rabbit hole and actually believe what he once knew to be untrue.
For decades, when he was a publicity-seeking developer and social-climbing Manhattan playboy, Trump's method was to fabricate his own reality; he even called gossip columnists and pretended to be a publicist named "John Miller" or "John Barron" in order to sing his own praises.
But he employed this shtick with a wink and a smile, knowing it was all a game. Increasingly he sounds and acts as if he thinks his make-believe is real.
One of the things that first drew attention to Trump as a presidential candidate was his public speaking style — free association, basically, with no discernible filter between brain and lip.
Follow one of his speeches and you can track how his mind works. On Monday, at a White House ceremony honoring Navajo code talkers, he bizarrely slipped in his "Pocahontas" slur against Sen. Elizabeth Warren (D-Mass.), who wasn't there and had nothing to do with the event.
On Wednesday, at a Missouri rally touting the tax bill, he came to a line about how it would add "rocket fuel" to the economy, paused a second, and then reprised his "rocket man" insult of North Korean leader Kim Jong Un, whom Trump went on to call a "sick puppy."
Kim's state-controlled media has called Trump an "old lunatic." That the rival nuclear-armed leaders speak the same language is not comforting.
Maybe Trump is rattled by the Great Reckoning on sexual harassment and assault. Maybe he is worried about the steamrolling Robert S. Mueller III investigation. Or maybe his mental state is just deteriorating.
Whatever the problem is, it's serious — and it's getting worse.
