In a recent interview in The New Republic, President Obama said this about the politics surrounding gun control:
That does not mean that you don’t have some real big differences. The House Republican majority is made up mostly of members who are in sharply gerrymandered districts that are very safely Republican and may not feel compelled to pay attention to broad-based public opinion, because what they’re really concerned about is the opinions of their specific Republican constituencies.
Obama expressed a common view: that gerrymandering has created a bunch of safe seats for each party, making representatives responsive only to their partisan base and unwilling to forge bipartisan compromises.
It would be nice if this view were true, because it would suggest a clear solution to our polarized politics: draw more competitive districts. But unfortunately it is not true. The most important influence on how members of Congress vote is not their constituents, but their party. This makes them out-of-step not only with the average American — the “broad-based public opinion” that Obama mentioned — but also, and ironically, with even their base. Members are more partisan than even voters in their party.
The easiest way to see how little constituency matters is to compare how representatives vote to the partisanship of their constituents. Here is what the 113th House looks like so far, based on calculations (pdf) by Stanford political scientist Simon Jackman