Biden would give a speech and fumble at some point (as he had done his entire life, dealing with a speech problem) and the press would report the hell out of it

There's a difference between a stutter and completely forgetting what you're trying to say every 3 words.

There was a conspiracy of silence around how pudding-brained Biden was until he dropped out. For 5 years yall gaslighted anyone who mentioned it by pointing at him reading prepared speeches while the guy couldn't talk to the press after like 4pm.

That's not to say Trump isn't senile, it comes through every time he goes off-script.