As far as tough political fights go, Sen. Tom Coburn, has seen more than his fair share and often with members of his own party, though even this latest kerfuffle would cause plenty of Republicans to go weak in the knees. It's a fight pitting the feisty Oklahoma Republican against the influential anti-tax advocate, Grover Norquist, and his Americans for Tax Reform (ATR), locking both conservative icons in a bitter feud that could signal an ominous battle ahead within the GOP as the nation nears its debt ceiling.

And neither man appears ready to back down any time soon.

First, it was a bill calling for the elimination of ethanol subsidies. Now, the Oklahoma Republican, a member of the bipartisan Senate debt reduction group called the "Gang of Six," is supporting revenue increases (aka: tax hikes) as part of a comprehensive solution to the debt problem.

Both are politically-risky moves, but Coburn is a self-described citizen legislator and term-limits champion who does not plan to seek a third term. He has charged ahead, albeit with some rhetorical contortions along the way on the tax issue.

At the root of the fight, ATR's "taxpayer protection pledge," which it seeks from incoming freshmen during campaign season. It's practically a GOP right of passage to sign on, and Coburn, along with his other two GOP Gang members, Saxby Chambliss of Georgia and Idaho's Mike Crapo, are signatories.

The pledge specifically says that signatories must "oppose any and all efforts to increase the marginal income tax rates for individuals and/or businesses" and must "oppose any net reduction or elimination of deductions and credits, unless matched dollar for dollar by further reducing tax rates."

So it's that second part of the pledge that has Coburn in hot water with Norquist, who immediately called on the Oklahoman to drop out of the Gang when it was revealed that the group would be supporting the elimination of some popular tax credits in favor of lower tax rates (though not dollar-for-dollar).

Coburn first told NBC's "Meet the Press" on Sunday that there would be no tax increases in the group's compromise but then added a head scratcher, saying, "If there is a net effect of tax revenue, that would be fine with me."

When asked if he had violated the ATR pledge, Coburn rhetorically asked, with his trademark defiance, "Which pledge is most important... the pledge to uphold your oath to the Constitution of the United States or a pledge from a special interest group who claims to speak for all American conservatives when, in fact, they really don't?"


Norquist seethed in an interview with Politico saying, "Coburn said on national TV today that he lied his way into office and will vote to raise taxes if he damn well feels like it never mind what he promised the citizens of Oklahoma. Sen. Coburn knows perfectly well that the pledge is not to any organization but to the citizens of his state. He lied to them, not to Americans for Tax Reform."

Coburn's spokesman labels Norquist the "chief cleric of sharia tax law."

And the feud goes on.

For any chance of success, though, the Gang is going to need more than a handful of Republicans to support a compromise. But the Coburn-Norquist showdown could scare some away if the group arrives at a grand bargain. Only seven of the 47-strong Senate GOP conference have not signed the pledge: Indiana's Richard Lugar, Charles Grassley of Iowa, Maine's Olympia Snowe and Susan Collins, Mississippi's Thad Cochran, Wyoming's John Barrasso, and freshman John Hoeven of North Dakota.

Even if all seven were to join all 50 Democrats in a product that contained tax hikes of any variety (and that is one large "if"), that would still leave supporters searching for a crucial three votes to overcome an assumed filibuster.

Both Senate Minority Leader Mitch McConnell, R-Ky., and House Speaker John Boehner, R-Ohio, have ruled out tax increases in this weak economy, and unless the duo is merely positioning for a tough fight, Congress is in for a rough road ahead. And as Democrats are not likely to give in on the tax issue, and with the caucus experiencing its own internal debt ceiling wrestling match, a vote to increase the nation's borrowing limit could very much be in jeopardy.