Like Sides, Nate Cohn finds evidence that the debates are over-hyped:
Why haven’t the debates had a greater impact? It appears that most voters make up their minds before early October, usually the onset of debate season. In this environment, debates are more likely to reinforce existing perceptions rather than shake up the race. Presidential elections may be nearly as expensive as small wars these days, but the real battlefield is not the debate stage.
The Dish 