Rep. Sullivan (R-Okla.) went down Tuesday in a surprise loss to a political newcomer.
The often heated conflict between Mike Huckabee and the Club for Growth is coming to a boil this month.
Five states hold primary contests Tuesday, with congressional contests taking the spotlight from the GOP presidential race.
Jesse Kelly, an Iraq war veteran and project manager, edged out three other Republicans vying to finish Giffords's term.
GOP presidential candidate Newt Gingrich’s biggest donor contributed $5 million with his wife to a Republican super-PAC.
Sheldon and Miriam Adelson donated the money to the Congressional Leadership Fund in February, Federal Election Commission (FEC) filings show. The Congressional Leadership Fund is a conservative super-PAC that is not earmarked to support or oppose a single candidate.
I'm not going to put any pressure on Rick, but I'd love his endorsement," the former House Speaker told reporters Saturday.
A wave of high-profile endorsements, coupled with beautiful weather and brisk turnout, should help Romney build on his delegate lead.
Santorum tried Sunday to translate his Louisiana victory into momentum as his campaign heads into much tougher terrain.
Haley Barbour said Mitt Romney is “finally a real front-runner” in the race for the GOP nod.