Although all these authors see polarization, none do a good job fully explaining the causes of polarization. I think the problem is not party polarization, as these articles seem to think. The problem lies, in my mind, with the fact that there is no outlet for moderates of either side, and as moderate politicians are sidelined moderate voters become disengaged, further exasperating the problem.
With elections framed as a zero sum game in a majoritarian electoral system, the catch all parties, which we first learned about in Andolino and Blake, have become a necessity for politicians survival, but this restricts flexibility for the broad range of opinions on both parties to work together to find compromise. The use of two parties means that a wide range of opinions are stifled. McCarty says that on a liberal conservative scale, according to the median voter theorem, gridlock should not exist, but these two dimensions do not do the political, social, and economic beliefs of American justice. The electoral system and the institutions of the legislature and party system have reinforced the power of the parties.
Gerrymandering is one instance of how the system has continuously reinforced polarization. In order to gain further security for electoral seats, as McCarty mentions, redistricting has created more homogeneous districts, further reinforcing the polarization of parties. Even through Americans have extremely low approval ratings for Congress, and always want to "throw out the bums," they tend to like their own representatives, meaning there is little change.
These problems of overly homogeneous districts, disengaged moderates, and elections as a zero sum game, have defined our two party system to become polarized. How might polarization and gridlock differ between a two party system and multi-party system? Is gridlock a result of formal and informal institutions or matter of political culture?