Sen. John Cornyn (R-Texas), head of the National Republican Senatorial Committee, is warning Republican senators that if they don't support banning earmarks, he can't promise them support from the NRSC in future primary races.
"All incumbents need to be prepared for primaries," Cornyn told the National Review.
"It would be a bad idea to depend on anybody other than yourself to help in a primary," he said. "Our job is mainly to pick up seats. My hope would be that our incumbents will be prepared and able to (run in a primary) without financial assistance from the NRSC."
Eight Republican senators yesterday joined with most Democratic senators toa GOP-sponsored bill that would have placed a two-year ban on Congressional earmarks.
The Republicans who voted against the measure were Sens. Thad Cochran (Miss.), Susan Collins (Maine), James Inhofe (Okla.), Dick Lugar (Ind.), Lisa Murkowski (Alaska), and Richard Shelby, as well as outgoing Sens. George Voinovich (Ohio) and Bob Bennett (Utah).
Of those senators, only Lugar is up for re-election in 2012. Some have already speculated that Lugar could face a primary challenge.
Bennett lost his re-election bid to a Tea Party-backed challenger, and Murkowski also lost her Republican primary this year to a more staunch conservative -- but she managed to win her general election write-in campaign (pending court challenges from Joe Miller).
As Washington increases its efforts to put its financial house in order,over the issue of earmarks.
Earmarks are requests by lawmakers for funds to be directed to their districts for specific companies or projects, and they account for less than one half of one percent of the federal budget.
Republicans in both the House and the Senate adopted voluntary earmark bans in the Spring, but GOP lawmakers from both chambers have violated the commitment. Republicans have also already adopted a voluntary earmark ban for the next Congress.
Stephanie Condon is a political reporter for CBSNews.com. You can read more of her posts here. Follow Hotsheet on Facebook and Twitter.