I don't  know. I think if we wanted a strong representative in the debates we would have chosen Bernie Sanders. This was not criteria that came into play in the choice of Biden. Biden is a middle of the road, steady as she goes, type. I think that was his big selling point. Not that he was the best choice...he was the least scary. He was mostly horrible in the Democratic primary debates so people knew he would stink, or should have known he would stink, in a debate with Trump. Trump imploded, went berserk and had all the charm of a rabid animal...which is what he is. So, Biden had a really low bar...look like a normal human being. Mission accomplished. Biden won the debate. People saw and heard Trump and essentially thought "Holy shit, this guy is enraged and insane." 

The only thing that would have made Trump's performance any more wacko was if he pissed or took a shit on the stage and ran over and started trying to gnaw off one of Biden's arms.