Incumbency in Congress is a fortress rarely breached, particularly in primaries. In the 2012 elections, even amid record-low approval ratings, primary voters tossed only one senator and five members of the House from office (not including those races featuring two incumbents sqauring off because of redistricting).
The odds are clearly in favor of the members. Still, primary voters give the boot to at least some lawmakers nearly every cycle. For those facing electoral threats from within their own party, the pressure is especially acute as they return to their districts and states for the August recess. This month marks one of the better, prolonged periods for them to make a positive impression back home.
Primary losses often come out of nowhere (witness Rep. Cliff Stearns, R-Fla., who was dealt a surprise defeat last year). But with the 2014 primaries less than a year away in most states, here is a list of the members of Congress who appear most vulnerable to losing the nomination. . .