Norquist said Democrats will never agree to the negotiating position of Graham and other Republicans, calling the demand for entitlement reforms akin to a "pink unicorn that doesn't exist."
The political risk for Republicans to going against the no-tax pledge comes from angering Norquist and other conservatives who can target them in GOP primary campaigns in 2014 and beyond.
Norquist said Monday his group would "certainly highlight who has kept their commitment and who hasn't" when re-election time comes.
"The key here is whether or not the Republicans will move away from the ideologically rigid position, which has been the Grover Norquist pledge," Democratic Sen. Carl Levin of Michigan told NBC on Sunday. "You've got to raise additional revenues, including tax rates on the wealthy. They have to go up. Either real tax rates or effective tax rates, there are ways of doing that."