He wasn't invading or threatening to invade multiple countries at a time, including those of allies.

Yes, we did. And that discussion had a most definite conclusion.

Invading a NATO ally was never on the table.

No body would do that, only an insane person.

Imagine how much better things would be if we did have that discussion. Lets not make the same mistake twice

We did have that discussion and almost certainly the DNC also had it with more than a handful of media appearances written off as gaffes. They decided their best chances were to stick with Biden.

Biden was ostensibly too old when he became President, but he hadn't started the obvious decline that we all witnessed in 2024.

And I still would much rather have had Biden for those four years than have had to face what we're facing now with Trump back then. Except with Trump being 4 years farther away from death than he is now...

Yes, actually. Enough people did (media, dnc leaders and supporters) have that discussion, to the point that Biden did not run for re-election.

There were A1 stories about his age and mental acuity constantly. The discussion was so intense that Biden dropped out of the presidential race.

Fucking endlessly, yes.