Growing Republican support for raising taxes to help reduce the deficit has prompted a GOP identity crisis, sparking a clash within the party over whether to abandon its bedrock anti-tax doctrine. 
 
 Tensions have mounted in recent days as two of the GOP’s most fervent anti-tax stalwarts on Capitol Hill — Sen. Patrick J. Toomey (Pa.) and Rep. Jeb Hensarling (Tex.) — have lobbied party colleagues behind the scenes to forgo their old allegiances and even break campaign promises by embracing hundreds of billions of dollars in tax hikes. 
 
 The two conservative lawmakers have pushed the increases as part of their work on the bipartisan congressional “supercommittee” tasked with finding at least $1.2 trillion in deficit reductions by a Thanksgiving deadline. Their plan, which also addresses entitlement spending, would generate at least $300 billion in new tax revenue over the next decade by overhauling the tax code to lower rates but also eliminate deductions and loopholes. 
 
 Their work has been met with a furious backlash as fellow conservatives inside and outside Congress expressed amazement that two of their biggest allies appear now to be foes. 
 
 “We’ve not had a conversation like this within the party in two decades,” said Rep. Patrick T. McHenry (N.C.), who on Wednesday gathered signatures from about 70 House Republican colleagues for a letter to the supercommittee leadership, calling any tax increase “irresponsible and dangerous to the health of the United States.” 
 
 Describing Hensarling as a “mentor,” McHenry added: “It’s a very tough situation.” 
 
 The conservative group Americans for Prosperity, which has fought taxes, began a campaign targeting 40 House Republicans who have expressed an openness to new taxes. The group invited constituents in Virginia and Florida to call in to telephone town hall meetings Wednesday night and purchased radio ads in five states charging that the members “don’t get it” when it comes to tax policy. 
 
 Critics say that giving any ground on taxes would violate party doctrine that has not been challenged since President George H.W. Bush broke his “read my lips” pledge as part of a 1990 budget deal. 
 
 Although it’s not clear how many Republicans are willing to raise taxes, the numbers have been growing in the House and Senate. Activists say they fear that the presence of rock-ribbed conservatives in that camp and support in the business community for a deal of some sort could be spurring widespread defections. 
 
 More Republicans moved Wednesday to push their party toward accepting new taxes — putting the issue in historic terms. 
 
 “This is about more than money,” said Sen. Lamar Alexander (Tenn.), a member of the Senate’s GOP leadership team. “It’s about whether the president and the Congress can competently govern, about whether we can face up to the biggest problem facing our country and, working together, can we solve that problem?” He added that both parties “need to put more on the table and get a result.” 
 
 As of Wednesday, the fate of the proposal backed by GOP supercommittee members was uncertain. Democrats rejected it last week, demanding more new taxes than the Republican panel members had been willing to offer. But negotiations continued, and Hensarling told reporters late in the day that he was “willing to look at any offer” from the other party. 
 
 GOP aides cautioned that the shifting ground on taxes has come about only because of the unique nature of the supercommittee. 
 
 Party leaders wary of Congress’s dismal approval ratings are loath to appear incapable of deficit reduction. Moreover, Republicans are worried about the deep automatic spending cuts to defense programs that would be triggered if the committee fails to reach a deal. 
 
 Still, officials and leading activists conceded Wednesday that even in this unusual context, the willingness of conservatives to compromise on taxes could forever change the debate within the party. 
 
 After all, it was Toomey, who, before his 2010 campaign for Senate, headed the Club for Growth, a pro-business group and pillar of the conservative economic movement. He has been one of Washington’s leading advocates of tax cuts. 
 
 “You’ve got Toomey, the most conservative member of the supercommittee, saying that under certain circumstances he’d be willing to raise taxes. That’s a big deal,” said Phil Kerpen, vice president of Americans for Prosperity. 
 
 “The most important part of the Republican brand is that they won’t raise taxes,” Kerpen added. “Some say this is a unique situation. Well, people won’t get the nuances. They’ll just see both parties are willing to raise taxes.” 
 
 Toomey could not be reached for comment Wednesday. He told “Fox News Sunday” over the weekend that his plan, which he said was “contingent on pro-growth tax reform,” was better than striking no deal with Democrats. 
 
 Any loosening of the GOP’s firm stance on taxes would sharply alter the political dynamics of the party. This change would mark a turnaround, just a year after the rise of the staunchly anti-tax tea party movement propelled Republicans into the House majority. Party activists note that Bush’s 1990 tax deal depressed conservative voter turnout in the next election, contributing to his defeat. They warn that a similar transgression could again deflate the party base, leading to President Obama’s reelection next year and costing Republicans the House. 
 
 A GOP aide, speaking on the condition of anonymity to discuss internal party deliberations, said the openness to tax increases would not “wipe away” the “very strong fundamental view about taxes.” And yet, the aide added, “It does change the conversation within the context of deficit reduction, and it will have implications.” 
 
 Adding to the dilemma facing many Republicans is their party’s long embrace of the Taxpayer Protection Pledge, which was created 25 years ago by anti-tax activist Grover Norquist and remains a rite of passage for Republican candidates at all levels. The GOP supercommittee plan appears to violate the pledge’s requirement that members oppose “any net reduction or elimination of deductions and credits, unless matched dollar for dollar by further reducing tax rates.” 
 
 Norquist said GOP leaders have assured him that they will not support a tax increase. But some in the party say they no longer feel bound by the Norquist pledge. 
 
 “I want my constituents to know that I am not in favor of raising taxes. That’s why I signed that pledge,” said Rep. Charles F. Bass (N.H.). “And I if I have to break that pledge for some reason, it would be because I think there’s a far greater good associated with it, and I’m willing to bear the consequences of that.” 
 
 Rep. Steven C. LaTourette (Ohio) signed the pledge in 1994, long before he said he could envision today’s economic turmoil. “Circumstances change,” he said. 
 
 More from PostPolitics: 
 
 Decoding supercommittee terms 
 
 Three possible paths for the supercommittee’s future 
 
 Wonkblog: The real cause of ‘regulatory uncertainty’ 
 
 Supercommittee GOP co-chair walks back comments on revenue 
 
 Staff writer Rosalind S. Helderman contributed to this report. ||||| Leaders say they’re not ready to take over supercommittee negotiations 
 
 By Russell Berman - 
 
 Congressional leaders said they have yet to take over deadlocked supercommittee discussions that are going nowhere fast. 
 
 The lingering stalemate has prompted suggestions that House Speaker John Boehner (R-Ohio) and Senate Majority Leader Harry Reid (D-Nev.) will have to take over the negotiations from the 12 members that they, Senate Minority Leader Mitch McConnell (R-Ky.) and House Minority Leader Nancy Pelosi (D-Calif.), appointed to the committee. 
 
 Supercommittee Democrats and Republicans have continued to meet separately, but have not met together for days, with a Nov. 23 deadline for reaching a deal fast approaching. Sources say side discussions are continuing, but doubts are growing that the group will be able to meet even its minimum requirement of $1.2 trillion in deficit cuts. 
 
 Boehner said congressional leaders who created the deficit supercommittee have a responsibility to help it succeed, but stopped short of saying they would take over the deadlocked discussions. 
 
 The Speaker has been heavily involved on the Republican side of the negotiations, meeting frequently with GOP members of the panel, though he has resisted the perception that he is running the show. 
 
 “Don’t suggest that we haven’t been involved,” Boehner told reporters Thursday at a news conference, noting the amount of discussion he’d had over the last two months with supercommittee members. 
 
 “The leaders created this, and frankly I think the leaders have some responsibility to help the committee succeed, and that is what we’ve been doing,” Boehner said. 
 
 “They’re well aware of what we’re willing to do,” he said, before quickly adding: “You can lead a horse to water but you can’t make him drink. The problems we’ve had all year is getting to ‘yes.’” 
 
 The two sides appear far apart on the key issue of how to balance spending cuts and tax hikes, and Democrats on Thursday sought to hammer home their argument that a GOP divide over taxes is hampering progress toward a deal. 
 
 Sen. Patty Murray (D-Wash.), co-chairman of the supercommittee, said the challenge is for Republicans to resolve their differences on taxes. 
 
 
 
 
 
 Separately, Pelosi used her news conference to hit Republicans as more beholden to Grover Norquist and his no-tax pledge than to their constituents and country. 
 
 
 
 
 
 “There are some who think or have suggested that the oath to Mr. Norquist is more important than other oaths that members take,” said Pelosi, who noted automatic cuts to defense spending would be triggered without a supercommittee deal. 
 
 Republicans are keen on avoiding those cuts, but there is turmoil within the GOP over agreeing even to the deal put forward by supercommittee Republicans. 
 
 That proposal would lower marginal tax rates permanently, giving the wealthiest tax bracket an 8-percentage-point tax cut. It would also limit deductions, raising $300 billion in new net tax revenues. 
 
 Some Republicans say that is going too far, and the conservative anti-tax group Americans for Prosperity announced this week that it was targeting 40 GOP lawmakers in the House whom the group believes could agree to higher taxes. The Americans for Prosperity campaign includes radio advertisements in a number of states. 
 
 Boehner, as he has consistently, laid blame on the Democratic side, saying both the White House and the party’s congressional leaders have been unable to accept GOP proposals. He said there’s “been exactly one proposal on the table in the committee. That proposal came from the six Republican members, House and Senate.” 
 
 While Democrats have made proposals, he noted that the party’s supercommittee members have never coalesced around a plan. 
 
 Boehner offered no new details on the current state of negotiations and declined an opportunity to clarify how much new tax revenue the GOP is willing to generate from an agreement. 
 
 He did say that he remained opposed to using budget savings from the winding down of the wars in Iraq and Afghanistan to pay for new spending, as Democrats have suggested. 
 
 “I’ve made it pretty clear that those savings that are coming as a result of winding down the war in Iraq and Afghanistan should be banked, and should not be used to offset other spending,” he said. 
 
 New end-of-year spending to extend the payroll-tax cut or unemployment insurance benefits, or to address Medicare reimbursement rates, Boehner said, must “be done in a fiscally sound manner. Period.”
– The proposal that super committee Republicans put forth to raise about $300 billion in new tax revenues may not have been enough to win over Democrats, but it’s been more than enough to stir up dissension in the GOP ranks, with anti-tax hardliners suddenly at odds with long-time compatriots Pat Toomey and Jeb Hensarling, the Washington Post reports. Rep. Patrick McHenry, who considers Hensarling his “mentor,” yesterday got 70 House Republicans to sign off on a letter declaring any tax increase “irresponsible and dangerous.” “We’ve not had a conversation like this within the party in two decades,” McHenry says. The conservative group Americans for Prosperity, meanwhile, has been pressuring the 40 House Republicans who have expressed openness to tax cuts, urging constituents to call them, and purchasing radio ads in five states. But other Republicans are pushing their party to compromise. “This is about more than the money,” said Lamar Alexander. “It’s about whether the president and the Congress can competently govern.” (Meanwhile, the panel's deadline gets closer with no deal in sight, notes the Hill.)