What did Donald Trump do today?

He forgot about a fake tariff he'd already "announced," and announced it again.

This morning, Trump blogged that he would be "imposing a 100% Tariff on any and all movies that are made outside of the United States."

How exactly a tariff would be imposed on an abstract intellectual property like a movie is… unclear, to say the least. Putting a tax on American distributors, or a sales tax on ticket prices, would require a new law entirely, one that Trump would have no chance of getting passed. Trump didn't explain, nor did he say what would count as an "American-made" film. That's important, because any given film might have some part of its production outsourced to a foreign company—including routine business services having nothing to do with the movie itself—and those also aren't subject to tariffs. 

Of course, even if these taxes could be imposed, they'd just be passed along to American (and only American) consumers, like all other tariffs Trump has imposed. And in reality, upsetting the balance of the world film industry could only hurt American studios, which are a major exporter of intellectual property through their movies.

But there doesn't seem to be any danger of Trump acting on this tweet-proclamation in any event: he'd already made it once already, back in May, and had apparently forgotten that he'd done so. All the same questions came up then, and the White House simply dropped the matter, leaving Trump to come up with the idea all over again four months later.

Why does this matter?

• Forgetting that you've done (or not done) something, and returning over and over again to the same thoughts, are clear signs of cognitive decline in elderly people.  

• Just because a policy is too stupid or damaging to ever actually be implemented doesn't mean it's great to have a president proposing it.