The Confederate flag is still dogging John McCain.

A third-party group that supports the flying of the Confederate flag has started running radio ads in South Carolina slamming McCain -- and to a lesser extent Mitt Romney -- for criticizing the flag.

The issue of flag rights popped up again this week when McCain was confronted Wednesday by protesters about his opposition to the flag, which some consider a racist symbol and others consider merely an expression of Southern pride. A day later, Republican rival Mike Huckabee said he supports South Carolina's state right to do what it wants with the flag, and the ad praises Huckabee for that stance.

"Mitt Romney is trying but when it comes to bashing the Confederate flag he can't hold a candle to John McCain. McCain has been doing it, calling the flag a racist symbol for years, and he is at it full steam ahead," says the ad, run by a group called Americans for the Preservation of American Culture. "After McCain, Arkansas Governor Mike Huckabee's stand is a breath of fresh air."

Click here to see the Confederate flag ad on the Talking Points Memo Web site.

South Carolina holds its primary Saturday, and McCain and Huckabee are locked in a battle to claim victory in the first-in-the-South primary.

Speaking in Spartanburg, McCain on Wednesday defended his opposition eight years ago to the flying of the Confederate battle flag over the South Carolina state capitol in Columbia.

Several protesters aggressively waved Confederate flags at McCain's bus procession as it arrived for campaign events in Greenville and Spartanburg and passed out literature recalling McCain's April 2000 call for removal of the flag from atop the South Carolina statehouse.

The dispute became an issue in the presidential contest that year as McCain waged a losing battle in South Carolina against then Texas Gov. George W. Bush. The flag was subsequently moved and now is displayed elsewhere on the statehouse grounds.

Huckabee said in Myrtle Beach Thursday that the federal government should stay out of disputes over the Confederate flag in South Carolina.

“You don’t like people from outside the state coming in and telling you what to do with your flag,” he said.

“In fact, if somebody came to Arkansas and told us what to do with our flag, we’d tell ‘em what to do with the pole, that’s what we’d do,” Huckabee said.

The Associated Press contributed to this report.