Biden is an old man who is slowing down, but I believe we might be residing in separate echo chambers regarding this issue because I see plenty of videos of him answering questions from the press, interacting with people in formal and relaxed settings seeming very much alert and capable of cognitive functioning, and actually being quite forceful on setting the record straight as he sees it. I do not get the impression of Biden being a mindless marionette except in highly selective montages produced by Fox News and partisans on Twitter.