Nothing riles up the tea party chattering class like a broken pledge against raising taxes.
After years of opposing higher taxes on anyone, Republicans now are under pressure to work out a comprehensive agreement to reduce the nation's chronic federal deficits and debt.
That means a compromise with Obama and Democrats, who insist on more tax revenue being part of a package that includes spending cuts and entitlement reforms.
Facing imminent unpopular scenarios such as higher taxes for everyone and further cuts in military spending, the negotiations taking place behind closed doors in Washington have new impetus to produce results.
Obama's victory this month with a slightly stronger Democratic majority in the Senate and a slightly weaker Republican majority in the House signaled general public acceptance of the president's main campaign theme: raising more tax revenue from the rich as part of a deficit-reduction package.
However, the new Congress to be seated in January includes 39 senators, including Chambliss, and 219 House members who have signed the anti-tax pledge pushed by Grover Norquist of Americans for Tax Reform, according to the group's website.
The House total constitutes a narrow majority in the 435-seat chamber, though
some members have denounced their allegiance to the pledge.
"I care more about my country than I do about a 20-year-old pledge," said Chambliss, a veteran Georgia Republican.
Chambliss acknowledged that Norquist and Americans for Tax Reform will likely work against his re-election because of the issue.
"But I don't worry about that because I care too much about my country," Chambliss said, adding that he was "willing to do the right thing and let the political consequences take care of themselves."