Science magazine reports on a study* comparing voting by congressmen and women and their constituents' opinions. Two political scientists compared, district by district, the voting records of congressmen with results of a national opinion survey that asked questions nearly identical to bills voted on. The results were that members of Congress were more extreme than their constituents. In the 109th Congress (2005-6), dominated by Republicans, the median House member was more conservative than the folks that elected them. In the following Congress where Democrats regained control, the votes were more liberal than the constituents. This is called leapfrogging, because moderate views of the voters are leapfrogged as one party's extreme replaces the opposite extreme. In the new Congress starting January 2011 the Republicans are already shown by polls to be more extreme than the country as a whole. Why do people elect representatives that are more extreme than they are? Is it because we only have two political choices and they are becoming completely polarized?
* published in Amer. Polit. Sci. Rev. 104, 519 (2010).
