Biden may be an old man with a faulty memory... but Trump is a straight moron.
I don't say that as hyperbole either. Like, he's legitimately one of the dumbest public figures I've ever seen.
Remember that time in the press conference he asked if we should be injecting bleach?
Politico summary
I don't know anyone else in my life that stupid. That's one example off the top of my head.
Sadly, there's only two choices. I hate idiots, so I'll go with the other guy.