The debate was a long negative message. Undecided voters walk away.
In the face of negative attacks, candidates feel compelled to pursue a tit-for-tat strategy that can get out of hand. For example, in one study we showed how people compete for 30-second commercials on political television, their reaction when one candidate was in attack mode and the other remained positive was to favor the aggressive candidate. (The sample comprised attacks on both politics – on issues such as crime and unemployment – and on personal competence.) The candidates feel this intuitively. So when they are attacked, they attack themselves. The need to avoid appearing weak is very real. That explains why Biden, who initially tried to stay away from Trump’s volleys, ended up calling him a “clown”. This primal psychological response by partisans to a perceived threat from their own group makes it almost inevitable that the next presidential debate will pick up where the first left off.