"I can handle things. I'm smart! Not like everybody says, like dumb. I'm smart and I want respect!"

This morning's presidential Twitter outburst recalls those words of Fredo Corleone's in one of the most famous scenes from The Godfather series. Trump tweeted that his "two greatest assets have been mental stability and being, like, really smart," and in a subsequent tweet called himself a "very stable genius."

Trump may imagine that he's Michael Corleone, the tough and canny rightful heir--or even Sonny Corleone, the terrifyingly violent but at least powerful heir apparent--but after today he is Fredo forever.

There's a key difference between film and reality, though: The Corleone family had the awareness and vigilance to exclude Fredo from power. The American political system did not do so well.