Sen. Claire McCaskillClaire Conner McCaskillGreitens Senate bid creates headache for GOP The Hill's Morning Report - Biden tasks Harris on border; news conference today Missouri Senate candidate Eric Greitens tangles with Hugh Hewitt in testy interview MORE (D-Mo.) should change her anti-earmark, Rep. Roy BluntRoy Dean BluntThe Hill's Morning Report - Presented by Tax March - CDC in limbo on J&J vax verdict; Rep. Brady retiring Senate GOP to face off over earmarks next week Greitens Senate bid creates headache for GOP MORE (R-Mo.) said, putting him at odds not only with the Democratic lawmaker, but many Republican colleagues as well.

Blunt, in the early stages if his 2010 Senate campaign, defended the procurement of earmarks by Sen. Kit Bond (R-Mo.), the man Blunt is hoping to succeed in the Senate.

"I've never been nearly as effective at this topic as Sen. Bond, who's fought hard for our state," Blunt said in a radio interview with talk radio host McGraw Milhaven Wednesday morning. "But I certainly wouldn't be the person to say I'm not going to be out there competing for things that are good for Missouri."

"I would hope that Claire would change her mind on this," the former House Minority Whip added.

The support for earmarks could leave Blunt vulnerable to a primary challenge from his right. Many have speculated that former state Treasurer Sarah Steelman (R), who also ran for governor in 2008, could challenge Blunt.

McCaskill spoke on the floor of the Senate this afternoon against earmarks, and joined other lawmakers this morning at the White House to meet about cutting government waste.

Listen to audio of the interview here.