Trump has appeared to fall asleep during some meetings; amid others, he has drifted off-topic, launching into bizarre segues on interior decor or about whales and birds. His public appearances have lacked focus, and he has used speeches to ramble about how Barack Obama walks down stairs, or to invent stories about the Unabomber.

The unpredictable behavior has forced the White House to repeatedly defend Trump’s mental acuity, often in hyperbolic terms. Trump himself has bragged that he “aced” an assessment which tests for early signs of dementia, but over the course of his 11 months in office, examples of unusual behavior have piled up.

There was the case in mid-July, when Trump told a detailed story about how his uncle, the late professor John Trump, had taught Ted Kaczynski, better known as the Unabomber, at the Massachusetts Institute of Technology (MIT).

Another incident that raised questions about Trump’s state of mind came in September. Trump summoned the country’s top military commanders to a meeting in Virginia, and treated them to a speech touting his alleged successes before saying this:

America is respected again as a country. We were not respected with Biden. They looked at him falling down stairs every day. Every day, the guy’s falling down stairs.”

Trump continued:

I said: ‘It’s not our president. We can’t have it.’ I’m very careful, you know, when I walk downstairs for – like I’m on stairs, like these stairs, I’m very – I walk very slowly. Nobody has to set a record, just try not to fall because it doesn’t work out well. A few of our presidents have fallen and it became a part of their legacy."

"We don’t want that. Need to walk nice and easy. You not have – you don’t have to set any record. Be cool, be cool when you walk down, but don’t, don’t bop down the stairs. That’s the one thing with Obama, I had zero respect for him as a president, but he would bop down those stairs, I’ve never seen – da da da da da da, bop, bop, bop, he’d go down the stairs, wouldn’t hold on. I said, it’s great, I don’t want to do it. I guess I could do it, but eventually bad things are going to happen and it only takes once, but he did a lousy job as president.”