He's literally never been like this during his entire career though. Like you wouldn't get worse at giving speeches after being a senator or vp just because you're president. I don't think that's ever happened. It's something that comes with being a federal politician for like 40 years, or however long he's been a politician. Biden's never been particularly good at speeches, but his speeches 10 years ago are like night and day compared to him now. I'd maybe buy the idea that his stuttering got worse with age, most things get worse with age after all, but I don't think it's the pressure. If anything going after Trump should be less pressure because most people hated him. They were just happy to see him gone (at the start at least). I will say that maybe slurring can be a sign of a stutter depending on the kind of slurring though. The kind I'm talking about is the kind where you kind of just mush words together as if you're drunk.