Rebel in the Ranks

But when Thomas and his allies want something, they usually get it. In 2003, for example, as Republicans worked to add a prescription-drug benefit to Medicare, Thomas insisted on--and got--provisions allowing private insurers to compete with Medicare. White House officials say they are confident he won't torpedo Bush's Social Security plan. "The President has a longer fuse than most when it comes to him because, at the end of the day, he has produced a lot of results," says a senior White House aide. But Administration officials realize they will have to address Thomas' concerns, especially the reliance on payroll taxes to fund Social Security.

Thomas is cranky with both those below and above him, famously storming out of a meeting on Medicare when his House leadership bosses took control of negotiations. He's erratic too: he has occasionally broken down in tears, as he did when apologizing for the Capitol police incident, lamenting that his mother would have told him, "When they were passing out moderation, you were hiding behind the door." The son of a plumber, Thomas grew up in Orange County, Calif. He earned bachelor's and master's degrees in political science from San Francisco State University and then taught the subject at a Bakersfield, Calif., community college. In 1978 he won a congressional seat from Bakersfield and, on arriving in Washington, roomed with another college professor who had decided to enter politics, Newt Gingrich. Like Gingrich, he ached to be a House leader. After Republicans gained control of the House in 1994, Thomas took over the obscure House Administration Committee. In 2000 he ran a fierce campaign to leapfrog over a more senior Republican to take over Ways and Means. Thomas quickly established a reputation for intelligence--impressing and confounding colleagues with long-winded explanations of everything from car engines to Medicare reform--and for independence. That quality has now made him Bush's biggest new problem. --With reporting by Matthew Cooper, John F. Dickerson and Karen Tumulty/Washington