Interesting article in New York Times.
It may be the goodness of people, rather than totally the Constitution itself, that is saving us from the prospect of a ruler remaining in power in spite of the vote. People like independent judges and local officials doing their jobs; a lot of folks, even some Republicans, that protected us.
I'd add (not mentioned in the article itself) that the Constitution includes the Electoral College; an old institution that helped Trump get into power in 2016. That didn't happen in 2020, but once in power, Trump is the kind of leader who is doing whatever he can to stay in power.
It's people and honesty. Possibly it's the spirit of the law, more than always the letter of the law, that protects us.