Grover Norquist, the head of the conservative advocacy group Americans for Tax Reform, has been called the most powerful man in Washington, D.C. He is the keeper of what is known, simply, as The Pledge, a document containing signatures of Republicans who have vowed to never raise taxes under any circumstance. Those who dare to flout The Pledge incur Norquist's wrath, which usually comes in the form of a conservative primary challenger hell-bent on kicking the RINO out. The result? "It's been 22 years since a Republican voted for a tax increase in this town," Norquist recently bragged to The New York Times.

However, there are signs that Norquist's vise-like grip on party orthodoxy is weakening. Senator John McCain (Ariz.) recently said, with no small measure of disdain, that "fewer and fewer people are signing this, quote, pledge." Sen. Saxby Chambliss (Ga.) said Norquist has "no credibility." William Kristol, the influential editor of The Weekly Standard, recently admitted that "it won't kill the country if we raise taxes a little bit on millionaires." And all this is coming just weeks before what could be Norquist's greatest challenge yet: The fiscal cliff, which will see all the Bush tax cuts expire unless Congress reaches a budget deal.

President Obama, energized by his resounding election victory, has promised to follow through on his campaign pledge to raise taxes on those earning more than $250,000 a year. Polls show that a strong majority of Americans agree with Obama's proposal, and Republican leaders have conceded that new revenue should be part of any budget deal, even if they haven't yet caved in on raising tax rates. All in all, Republicans are looking very squishy on what used to be a united, inviolable anti-tax stance.

Norquist insists that's not the case. He has even claimed that it would violate The Pledge to close tax deductions that raise government revenue. However, for all his confident assertions, Norquist is desperately "leading a rear-guard action to prevent defections," says Dana Milbank at The Washington Post. Indeed, it appears increasingly likely that many Republicans will violate The Pledge in some manner, either by ending certain deductions or even raising rates.

Norquist's own lofty perch in Washington is at stake. Once elected officials violate The Pledge, there may be no turning back. After all, the only reason it has such a hold over the GOP is because everyone within the party sticks to it. "If the Norquist pledge is broken en masse, as seems likely, his bizarre source of political power disappears as well," says Jay Bookman at The Atlanta Journal Constitution.

Of course, it may be too early to write off Norquist, who over the years has shown remarkable tenacity and staying power. "This is not my first rodeo," he tells The Times.

Sources: The Atlanta Journal Constitution, National ReviewThe New York TimesSalon, The Washington Post