Polarization in safe states

There is an interesting posting in Andrew Gelman's The Monkey Cage indicating that legislators from Republican "safe states" tend to be more conservative than their constituents, legislators from Democratic "safe states" tend to be more liberal than their constituents, and legislators from "battleground states" tend to share the bimodal distribution of ideology of their constituents more closely. Senators tend to be more homogeneous in their ideology than members of the House of Representatives in the "safe states".

I have heard it commented upon in the past that the increasing number of safe constituencies in the United States has contributed to the increasing polarization of the Congress, and Gelman's data would tend to support that idea.

By the way, the blog is from this quotation:

Democracy is the art of running the circus from the monkey cage.
H.L. Mencken