Long before President Obama waded into the vociferous debate over a mosque near Ground Zero, a group of conservative writers and bloggers critical of Islam had seized on the issue and helped transform it into a national political spectacle.

While some have dismissed them as bigoted attention-seekers, their attacks on the proposed Islamic center in Lower Manhattan have gained currency in recent weeks among some Republican leaders. And their influence appears to be growing.

They are organizing a Sept. 11 rally against the mosque that will feature former U.S. House speaker Newt Gingrich. They advise the FBI and other government security agencies on the threats posed by Islamic radicalism, headline "tea party" events and attract millions of readers concerned or curious about Islam to Web sites with names such as Jihad Watch, Creeping Sharia and Stop Islamization of America.

"People on the Hill, their staff read these sites, they show their bosses. . . . They push these subjects into the spotlight, often at a time when major media isn't doing that," said Cliff May, a columnist and former spokesman for the Republican National Committee who runs a think tank focused on religious extremism and religious freedom.

The most colorful -- and perhaps most visible -- activist at the moment is Pam Geller, a former New York Observer publisher who has appeared in a bikini and a super-tight Superman costume challenging Islam.

Through her blog, Atlas Shrugs, television interviews and appearances at political rallies, Geller has become one of the chief organizers of opposition to the so-called Ground Zero mosque as well as efforts to build other Muslim prayer centers across the country.

Republican leaders including Sarah Palin, House Minority Whip Eric Cantor (R-Va.) and Gingrich have condemned the $100 million Park 51 Islamic Cultural Center, while Obama and New York Mayor Michael Bloomberg (I) have defended it. On Wednesday, House Speaker Nancy Pelosi (D-Calif.) added more fuel to the fire by saying she supports an investigation into how opposition to the mosque is being funded.

Geller has become a prominent voice in the debate despite the fact that she once promoted the view that Obama is Malcolm X's love child. She frequently warns that Muslims are trying to impose repressive sharia law on the United States, refers to the president's holiday message to Muslims as "Obama Ramadamadingdong" and promotes a Web site, Religion of Peace, that claims to tally the number of people killed around the world by Muslim extremists.

In Washington, New York and other cities, she has helped fund controversial taxi ads asking: "Is your family threatening you? leaveislamsafely.com."

Geller often partners with Robert Spencer, a best-selling writer who is less flamboyant but perhaps more influential.

Spencer, the author of "Stealth Jihad: How Radical Islam Is Subverting America Without Guns or Bombs" and "The Complete Infidel's Guide to the Koran," has consulted on Islamic extremism with government security officials, including the U.S. Central Command, the U.S. Army Command, the FBI and the Joint Terrorism Task Force, according to his Web site, Jihad Watch.

The site, which was launched in 2003, had its busiest month ever in July, with 2.9 million visitors, up from 665,000 a year ago, Spencer said.