I've been thinking about this, Trump has made two major unforced errors that will probably cost him the election. Picking JD Vance as VP is the obvious one, but agreeing to a debate with Biden before the convention was the really big one. Not doing this probably would have hurt him in the polls because it would have made him look cowardly, but he had plenty of time to recover. He probably could have spun it in a way his base would have eaten up, "Sleepy Joe is so terrible I don't even know if he is going to be the candidate, I'm not debating him until I know they aren't replacing him with Laughing Kamala or one of the other far left lunatics who want to destroy this country." It wouldn't have been hard to pull off.
The problem was he smelled blood in the water, he knew Biden was weak, and he wanted to move in for the kill. But he did it too early, he destroyed Biden too successfully, and now he has an opponent he is completely unprepared for. All he had to do was hold his fire for about two months to make sure Biden was doing just well enough that the party didn't feel compelled to get rid of him. But Trump couldn't help himself, he's a bully at heart, he senses weakness in one of his enemies and he just wants to kick them while they are down, ironically this is what helped him destroy an entire generation of Republican presidential hopefuls in 2016. But his complete lack of any ability to plan for the future has destroyed him here.
