Where do right-wingers get the idea that Biden suffers from dementia?

Well, here’s an article that counters claims of corruption on the right:

So that’s a cite related to the subject, and from a very reputable source. (They are non-partisan, which means both the right and left gripe about them, and even won a Pulitzer in 2009.)

Wilson should have resigned. His stroke meant that he couldn’t deal with the League of nations and the economy

Agreed and welcome.

After his stroke, Wilson avoided anything like this apparently impromptu speech where Biden mentioned the Brits:

While the Biden paragraph in question shows some grammatical weaknesses, it is not characteristic of dementia — and most of the speech is impressive.

It’s strange how a wkipedia account for Wilson"s VP Marshall says Wilson’s wife didn’t want to let on how how Wilson"s stroke affected him. Maybe his wife Edith was making decisions for him I guess. As you said it would have been better if he’d resigned since his doctor said he’d become very emotionally unpredictable after his stroke. It sounds like a crisis now as it was probably then.

Stuff happened a lot more slowly then. If some political or military problem loomed they’d have weeks to sort out replacing Wilson if he wasn’t up to the task.

That all changed with the advent of ICBMs.