I think the problem is, that the system was set up on the assumption that you’d have to be a semi-reasonable person to end up as president. Like there are checks an balances set up to reign in your dictators and evil genius types, but they didn’t really account for a complete moron getting in there and just running hog wild.
It’s a bit like setting up a really elaborate security system to catch any kind of sneaky burglar, and then someone just flattens your house with a tank for no reason.