Georgia Sen. Saxby Chambliss ditched Norquist's pledge last Thursday.
"I care more about my country than I do about a 20-year-old pledge," he told Georgia TV station 13WMAZ. "If we do it his way then we'll continue in debt, and I just have a disagreement with him about that."
Asked if he fears a possible primary challenge, Chambliss said, "I don't worry about that because I care too much about my country. I care a lot more about it than I do Grover Norquist."
"I'm all for the very wealthy paying more taxes," he recently told Washington Post's Wonkblog.
Coburn took direct aim at Norquist's "tortured definition of tax purity" in a July op-ed for the New York Times, arguing that the pledge is irrelevant.
"Senate Republicans -- and many House Republicans -- have repeatedly rejected Mr. Norquist's strict interpretation of his own pledge, a reading that requires them to defend every loophole and spending program hidden in the tax code," he wrote. "As a result, rather than forcing Republicans to bow to him, Mr. Norquist is the one who is increasingly isolated politically."
The South Carolina senator reiterated Sunday that Republicans should be willing to lower the debt with new tax revenues.
"I think Grover is wrong when it comes to, 'We can't cap deductions and buy down debt," he said Sunday on ABC's "This Week."
Despite the risk of a primary challenger in 2014, he remains vocal against the pledge and in favor of new tax revenue -- if Democrats agree to meaningful entitlement cuts.
"I'm willing to generate revenue," he said. "When you're $16 trillion in debt, the only pledge we should be making to each other is to avoid becoming Greece, and Republicans should put revenue on the table. We're this far in debt. We don't generate enough revenue."
The conservative Rep. Peter King (R-NY) said Sunday that the pledge is outmoded, declaring that "everything should be on the table" in an upcoming debt reduction deal.
"A pledge you signed 20 years ago, 18 years ago, is for that Congress," he said on NBC's "Meet The Press." "For instance, if I were in Congress in 1941, I would have supported a declaration of war against Japan. I'm not going to attack Japan today."
"I, myself, am opposed to tax increases," he said. "The fact is the speaker and the majority leader and the president are gonna be in a room, trying to find the best package. I'm not gonna prejudge it. And I'm just saying we should not be taking iron clad positions."
The shift makes King one of few House Republicans to disown Norquist's pledge.
On Sunday, Sen. John McCain (R-AZ) eased his anti-tax stance by saying he'd support a debt deal that raises revenues by limiting tax deductions and credits.
"I would be very much opposed to raising tax rates, but I do believe we can close a lot of loopholes," the party's 2008 standard-bearer said on "Fox News Sunday." He said that could be achieved by imposing "a limit on the amount of deduction on charitable giving, a limit on the amount you can take on your home loan mortgage deduction."
McCain didn't pointedly address Norquist's pledge but his remarks signal a break from it.
During a debate for his Arizona Senate race, conservative six-term Rep. Jeff Flake said he never signed Norquist's pledge even though he did. He went on to win the race.
"The only pledge I'd sign is a pledge to sign no more pledges," he said. "We've got to ensure that we go back and represent our constituents in a way -- I believe in limited government, economic freedom, individual responsibility. I don't want higher taxes. But no more pledges."
The former Wyoming senator co-chaired the White House fiscal commission which proposed trillions of dollars in new taxes -- and earned accolades from the Beltway establishment. He has fervently attacked Republicans for their allegiance to Norquist's pledge.
"For heaven's sake, you have Grover Norquist wandering the earth in his white robes saying that if you raise taxes one penny, he'll defeat you," he told CNN back in May. "He can't murder you. He can't burn your house. The only thing he can do to you, as an elected official, is defeat you for reelection. And if that means more to you than your country when we need patriots to come out in a situation when we're in extremity, you shouldn't even be in Congress."