It's important to separate two aspects of political division ("polarization"). The two political parties have become more divided. The economic crisis may have contributed a little to this, but it began in the 1970s. It's mainly a function of the increased coherence of the two parties. Conservatives in the south have moved from the Democrats to the Republicans, and liberals in the northeast have done the opposite. The two parties, which once were incoherent collections of individual candidates, now more closely resemble European parties with distinct ideologies.
The American public, by contrast, has not changed much in its degree of polarization, at least according to public opinion survey data. People on the extremes have gotten louder and more visible, but they haven't increased in number.
Wednesday, March 02, 2011
Lane Kenworthy on political polarization: