As we noted earlier, the House of Representatives has already twice passed legislation this year in violation of the "Hastert Rule."

The GOP leadership needed a majority of Democrats to pass legislation to avoid the fiscal cliff and to provide Hurricane Sandy relief aid to impacted communities. Between those two high-profile votes, there were 29 House Republicans who broke with the majority of their caucus and joined Democrats to pass the bills. 

These 29 "double-defectors" could be considered prime targets for GOP primary challengers, likely with support from Tea Partiers and other fiscal conservative groups such as the Club for Growth.

Interestingly, many of these lawmakers are already potentially vulnerable due to a recent leftward shift in their voting records. Of the 20 who were members of the House prior to 2011, 19 have a lower American Conservative Union rating for 2011 than their lifetime rating.

The 29 House Republicans who bucked their party twice:

Rodney Alexander (La.), Lou Bartletta (Pa.), Tom Cole (Okla.), Jeff Denham (Calif.), Charles Dent (Pa.), Mario Diaz-Balart (Fla.), Michael Fitzpatrick (Pa.), Rodney Frelinghuyse (N.J.), Jim Gerlach (Pa.), Chris Gibson (N.Y.), Michael Grimm (N.Y.), Richard Hanna (N.Y.), Jaime Herrera Beutler (Wash.), Peter King (N.Y.), Leonard Lance (N.J.), Frank LoBiondo (N.J.), Frank Lucas (Okla.), Tom Marino (Pa.), Buck McKeon (Calif.), Pat Meehan (Pa.), Tom Reed (N.Y.), David Reichert (Wash.), Harold Rogers (Ky.), Ileana Ros-Lehtinen (Fla.), Jon Runyon (N.J.), Jim Shimkus (Ill.), Chris Smith (N.J.), Don Young (Alaska), C.W. Bill Young (Fla).