Good one...updating list:

Reason Joe Biden won’t be able to participate in the debate.:
1 Comes down with a convenient case of “Covid” :TBD
2 Can’t remember his name: Check
3 Can’t form a complete sentence that makes sense: Check
4 Burisma Investigation indicates criminal actions: TBD  

GLP helpers:

5 The moderator will be positioned too far away to sniff.
6 He's busy interviewing accusers for Trump's supreme court nominee.
7 Children aren’t going to be attending.