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...