Reporting on presidential campaigns has become a kind of quadrennial ritual in which, after the election is long over, we get to go behind the scenes to understand what made the campaigns tick; what mistakes were made by the looser and what was done right by the winning team.The really good ones though, take us behind the scenes of the electorate itself.  They examine not just how power passes, but how the nature of the country changes every four years.  For Presidential votes are different than other kinds of elections. They are a kind of national gut check of the mood, temper, culture and divisions of the time.  They tell us about the candidates, but more importantly, the really good reporting also give us a snapshot of ourselves.That's what Washington Post Chief Correspondent Dan Balz has done in Collision 2012: Obama vs. Romney and the Future of Elections in AmericaMy conversation with Dan Balz: