I keep waiting for someone to state what to me is obvious- did someone slip him a Mickey? I can tell you candidly that when I was a teenager back in the 60’s I can remember instances of teenagers slipping lsd into foods or beverages and having someone else consume it. And it was easy! ( I just had my birthday yesterday making me 72! What a time it was! I literally, and I mean literally, grew up in Wayne’s World, aka Aurora, Illinois.)
I believe a deep forensic should be undertaken, examining the last few hours of Biden’s time before the debate.
Don’t forget that there is such a thing as date rape drugs.
Why did his performance improve in the second half of the debate? Because whatever he consumed started to wear off.
I can imagine that you may think this is absurd. The successful individual who accomplished this would expect this attitude to prevail if they were successful. Let’s not underestimate rogue countries. Remember Khashoggi. This stuff happens!
This, of course, somehow needs to be handled delicately. The right will spin it like an excuse for a poor performance.
If this is not the case, and he was functioning under his own steam, then that is even worse.
Be sure of the content of every food and beverage you consume.