WASHINGTON — The ad now running on televisions across South Carolina blasts U.S. Sen. Lindsey Graham, R-S.C., for advocating an increase in the income subject to Social Security taxes.

But the president of the group sponsoring the ads supported a bill four years ago — when he was a Republican congressman from Pennsylvania — that would have done exactly the same thing.

“I don’t see any comparison,” said Pat Toomey, president of the Washington-based Club for Growth.

“Social Security was nowhere near the front burner of any policy agenda” in 2001, he said. “It was important to get some momentum.”

But today, he says, Social Security is a domestic priority, so there is no need to jump-start the debate by talking about raising the income cap.

The ad is the latest example of how President Bush’s push to change Social Security — often called the “third rail” of American politics — has prompted infighting among Republicans.

In the ad, old-fashioned airplanes crash or flap useless wings. A man’s voice intones: “Lindsey Graham’s tax hike would hit millions of families, wipe out much of the Bush tax hike and punish small businesses.”

“A really bad idea,” the voice says.

“The ads are a really bad idea,” said Derrick Max, executive director of the Washington-based Coalition for the Modernization and Protection of America’s Social Security.

Max, like several Republicans interviewed for this story, does not favor raising the income cap. But he says the ads unfairly blame Graham for trying to find common ground with Democrats while working to overhaul Social Security with GOP-favored private accounts.

When Max saw the ad last week, he said he called Toomey and reminded him of his support four years ago for the “21st Century Retirement Security Act.”

That bill, which did not get far in Congress, called for private accounts that would allow workers to invest in stocks and bonds part of what they now send to Social Security.

It also would have raised the $90,800 cap in 2002 to $111,600 in 2004, and higher in future years.

Toomey told The State that he disliked that part of the bill but thought signing on to it was politically necessary to push the Social Security debate forward.

But, “that’s exactly what Lindsey is doing,” Max said.

Graham has said that if private accounts are going to gain needed Democratic support, Republicans must compromise. One way, he said, is to have richer people pay more Social Security taxes. He has suggested raising the cap from about $91,000 to $150,000.

“Those TV ads aren’t the way to solve problems,” he said. “I refuse to turn my job and independent thinking over to any special interest group.”

Toomey said Graham has faltered in his support for private accounts. He points to comments Graham made in the Washington Post last month critiquing the Bush administration’s strategy of first focusing on private accounts instead of Social Security’s general solvency problems.

“It’s always been a sideshow, but we sold it as the main event,” Graham told the Post.

Graham’s own Social Security plan, filed in Congress in January, includes private accounts — but no increase in the cap, which he is pushing separately.

Toomey has in the past challenged Republicans who had strayed, in his view, from conservative ideals.

In 2004 he nearly beat four-term U.S. Sen. Arlen Specter in the Pennsylvania GOP primary. In January he became president of the 5-year-old Club for Growth, which has angered some in the GOP for its willingness to take on Republicans.

Staff writer Lee Bandy contributed to this report. Reach Markoe at (202) 383-6023 or lmarkoe@krwashington.com.