A group founded by former Sen. Jim DeMint is targeting fellow South Carolina Republican Sen. Lindsey Graham, charging the two-term Republican with being insufficiently hostile to President Barack Obama's health care law.

The 61-second radio ad by the Senate Conservatives Fund popped up on Sunlight's Political Ad Hawk days after a tea party challenger announced she is entering the primary against Graham. The ad cites Graham's refusal to join Senate Republicans, such as Ted Cruz of Texas and Mike Lee of Utah, in an effort to cut off funding for the law. Graham, along with a number of other more mainstream Republicans, have urged a less confrontational approach that would not threaten a government shutdown.

"Obamacare is a job killer yet Lindsey Graham refuses to do what it takes to stop this liberal train wreck," the announcer on the ad intones.

Graham has irked some South Carolina Republicans by working across party lines on issues such as climate change and immigration. His primary opponent, 35-year-old Charleston consultant Nancy Mace, is portraying herself as an anti-establishment conservative — similar to the image of DeMint, who founded the Senate Conservatives Fund. After the 2010 elections, DeMint promised party leaders he would not use the fund to attack fellow Republicans, but since he left the Senate to head the Heritage Foundation, all previous pledges appear to be off. 

The Senate Conservatives Fund also has produced a similar advertisement against Republican Sen. Richard Burr, who is up for reelection next year in North Carolina.