WASHINGTON -- The GOP's image as a rigidly anti-tax party is softening. Spurred by federal debt worries in Congress, the shift conceivably could reshape the Republican Party's brand ahead of the 2012 elections, forcing tough decisions by its presidential candidates.

Some of the party's staunchest fiscal conservatives have surprised colleagues by saying targeted tax hikes are acceptable if they lead Democrats to accept deep government spending cuts.

Whether or not Congress' deficit-reduction talks succeed, the Republicans' offer has touched off a debate unlikely to end soon. The altered stance would upend party orthodoxy, which holds that deficits should be tamed entirely by spending cuts, with no tax increases.

Growing numbers of Republican lawmakers and strategists have grown wary of the no-exceptions position. They fear independent voters will abandon the GOP next year if it seems too rigid and beholden to the tea party. They also worry that another deficit-reduction impasse will further erode Congress' image, and Republicans might be handy election targets.

Some of those Republicans hope Democrats will agree to a deal that would include cuts to Medicare and, eventually, Social Security. Such a bargain might protect Republicans from so-called "Mediscare" attacks next fall, based on their embrace of an earlier GOP budget plan that would privatize and shrink Medicare for future beneficiaries.

Publicly, Republican lawmakers say they are motivated by the dire need to curb the deficit and reassure financial markets that the government can tax and spend responsibly.

Rep. Charles Bass, R-N.H., recently told NPR that he might renege on his pledge to oppose higher taxes, even if it hurts him politically. Bass also pledged to "defend America against enemies, both domestic and foreign. And I consider the debt crisis in this country to be a real threat to the future of America."