What did Donald Trump do today?

He trashed an outgoing Cabinet secretary at a Cabinet meeting.

There was a Cabinet meeting today, the first since the resignation of Defense Secretary James Mattis—although Trump has now decided to call that a firing. Mattis resigned in protest last month over Trump's sudden insistence on a pullout of American troops from Syria, which would amount to an abandonment of vulnerable American allies in the region.

Trump's opening ramble eventually turned to Mattis, about whom he said: "What's he done for me? How has he done in Afghanistan? Not too good. Not too good. I'm not happy with what he's done in Afghanistan, and I shouldn't be happy."

What Mattis has "done for" Trump in Afghanistan is carry out the Trump administration's policy. But it's not entirely clear what that policy is—as Trump himself demonstrated in the meeting when he bizarrely praised the Soviet Union's 1979 invasion of the same country. This is what Trump said about his long-term Afghanistan strategy:

We're gonna do something that's right. We are talking to the Taliban, we're talking to a lot of different people. But here's the thing... Russia is there. Russia used to be the Soviet Union. Afghanistan made it Russia, because they went bankrupt fighting in Afghanistan. Russia. So you take a look at other countries—Pakistan is there. They should be fighting. But Russia should be fighting. The reason Russia was in Afghanistan was because terrorists were going into Russia. They were right to be there. The problem is, it was a tough fight and literally they went bankrupt. They went into being called Russia again, as opposed to the Soviet Union, you know a lot of these places you're reading about now are no longer part of Russia because of Afghanistan.

In other words, Trump is saying that the United States—which funded, under President Reagan, the Mujahideen opposition to the occupying Soviet force—was on the wrong side of the Soviet-Afghan War. He also seems to be saying that the United States should not simply withdraw from Afghanistan, but that it should do so specifically in order to allow the Soviet Union and Pakistan to take control. (Trump himself suspended U.S. military aid to Pakistan because of its support for the Taliban.)

Put even more simply, Trump is siding with two adversarial countries—one of whom is an ally of the United States' enemy in Afghanistan—against the policy of every presidential administration, including his own, for the last 40 years.

Put as simply as possible, virtually none of what Trump claims to believe about Afghanistan is true.

So what?

• It's bad when an American president takes sides with the Putin (or Brezhnev) regime against the United States' interests.

• Only incompetent leaders blame their subordinates when their plans don't work.

• It's useful for presidents to have some knowledge of history, including the parts they were middle-aged adults during.