Moderate Republicans have been losing their seats.

Of 216 House Republicans who ran for reelection, only 14 were defeated, a mortality rate of just over 6%.

Members of the tea party caucus did even better than that; only about 5% were defeated. (The losers included Allen West of Florida and Joe Walsh of Illinois, two especially fiery members whose constituents ran out of patience.)

Which Republicans lost their seats? Moderates and moderate conservatives, disproportionately.

Among the incumbents who ran for reelection, 48 were members of a group called the Republican Main Street Partnership, nonradical conservatives who sometimes call themselves “center right.” Seven of those 48 lost their seats — a mortality rate of 15%, more than twice as high as Republicans in general.

When you add retirements and other departures, more than a dozen moderate conservatives won’t be coming back next year.
http://www.latimes.com/news/opinion/commentary/la-oe-mcmanus-column-moderates-in-congress-20121118,0,3405030,full.column