Party realignment on cultural issues is responsible for increased political polarization in presidential elections

The past twenty years has seen three government shutdowns and an unprecedented number of filibusters. While these trends seem symptomatic of increasing political polarization it is exceedingly difficult to measure the difference between the two parties over a long period of time. Using data from the American National Election Survey, Stefan Krasa and Mattias Polborn examine policy divergence in presidential elections between 1972 and 2008, finding a sharper contrast between the parties today. They attribute this divide to the realignment of both parties on cultural issues.