Lawrence O’Donnell kicked off his Wednesday night broadcast of “The Last Word” with a question: “If Donald Trump gets dementia, how will we know?”

Citing numerous confusing remarks that the president has made in recent days about everything from Federal Reserve Chair Jerome Powell to the Declaration of Independence.

Donald Trump’s mental decline, which is more and more obvious, started from such a low level of mental processing power that it’s hard to track his decline. It’s from low to lower.

O’Donnell went on to mock Trump for seemingly implying during a recent Oval Office press conference that the Declaration of Independence was written during the American Civil War.

We’ve always known that Donald Trump could not possibly pass a high school AP History course. We’ve always known that Donald Trump couldn’t pass any test in any high school history course. But now we know that he couldn’t possibly have passed a history test in my third grade at Saint Brendan’s Elementary School in Boston.

[…]

The psychiatrists promised us in the first year of the first Trump presidency that there was only one direction that his mental health could go. Every day, Donald Trump proves them right.