But with Americans now overwhelmingly supportive of tax hikes on their wealthiest fellow citizens as the U.S. faces yet another fiscal crisis, the unelected lobbyist's apparent death grip on the party seems to be faltering.
Several Republicans, including high-profile senators like Lindsey Graham and John McCain, are now expressing a willingness to defy Norquist and agree to tax increases as part of the so-called "fiscal cliff" negotiations currently under way on Capitol Hill.
The fiscal cliff is the term used to describe the confluence of expiring George W. Bush-era tax cuts and previously mandated budget cuts slated to take hold in January.
U.S. President Barack Obama wants to extend the cuts for those earning less than $250,000 while allowing rates to return to 1990s levels for the top two per cent of Americans who have an annual income higher than that.
Obama expressed confidence on Wednesday that some Republicans were beginning to accept that tax increases must be in the mix as they try to reach a deal on avoiding a fresh fiscal crisis in the new year.
"I'm glad to see ... that more and more Republicans in Congress seem to be agreeing with this idea that we should have a balanced approach," he said at the White House.
"The Senate has already passed a bill that keeps income taxes from going up on middle-class families. Democrats in the House are ready to vote for that same bill today. And if we can get a few House Republicans to agree as well, I'll sign this bill as soon as Congress sends it my way."
The notion of Republicans going along with tax hikes, however, has resulted in a full-fledged public brawl between one of the party's congressmen — Rep. Pete King of New York — and Norquist, head of the Americans for Tax Reform lobby group.
King earned the wrath of Norquist over the weekend, when the congressman dismissed his pledge as being out-dated.
"A pledge you signed 20 years ago, 18 years ago, is for that Congress," King said.
"For instance, if I were in Congress in 1941, I would have signed a ... declaration of war against Japan. I'm not going to attack Japan today. The world has changed. And the economic situation is different."
Norquist fired back.
"The pledge is not for life, but everybody who signed the pledge, including Peter King who tried to weasel out of it — shame on him," Norquist said on CNN.
"I hope his wife understands the commitments last a little longer than two years or something."
King called Norquist a "lowlife" for that remark.
Norquist, indeed, isn't going down without a fight —in breakfast remarks on Wednesday, he warned Republicans against having "their fingerprints on the murder weapon."
Republicans need to have a "credible" separation from any tax hike as part of an agreement to avoid the fiscal cliff, he said at a breakfast gathering hosted by Politico.com.
Norquist added that just because some Republicans are entertaining "impure thoughts" about raising taxes, he's not concerned that any of them will actually vote in favour of tax hikes.
"We have a spending problem, not a failure-to-raise-taxes problem."
All week, in fact, the 56-year-old Norquist has been sanguine in the face of suggestions that his pledge might be facing widespread rejection — not surprising, perhaps, given 95 per cent of congressional Republicans still support it.
When an online artist tweeted a painting of Norquist as a menacing, green-faced Wizard of Oz, his head looming large amid flames as capitulating Republicans knelt before him, he replied on Twitter: "My mom wants one."
Talk of rebellion is nothing new, Norquist added on CNN.
"I've seen this movie about 50 times before," he said.
"I get this every time someone burps. It always gets reported as all these guys have caved and said they're for tax increases. All it is happens to be a handful of people are having impure thoughts."
Democrats, meantime, launched an online petition on Wednesday to mobilize the public against Norquist and his anti-tax pledge. They're hoping to amass 250,000 signatures.
"Norquist's iron grip on Republicans in Congress is so strong that they're afraid to raise taxes on billionaires even one red cent," says an email sent Wednesday by the Democratic Congressional Campaign Committee.
Obama also hyped a White House Twitter campaign asking Americans how they'd be affected if their taxes increased by $2,200 a year, the sum an average family of four saved under the Bush cuts — savings that would be wiped out if the U.S. goes over the fiscal cliff in a few weeks.
Norquist's hold on the party is a curious one — he's viewed as one of the most powerful figures in the U.S. capital, despite the fact he's never been elected to public office or held a cabinet position.
Nor does his lobby group have deep pockets, spending only a few million dollars during the presidential election campaign compared to the hundreds of millions doled out by other pro-Republican donors.
And yet the Taxpayer Protection Pledge he unveiled more than 20 years ago has become a gun to the head of Republican lawmakers. A failure to sign the pledge signals an intention to hike taxes, a stance that can sound the death knell for a Republican politician.
Norquist keeps the original copies of every signed pledge in a fireproof vault for protection, and isn't shy about warning lawmakers that they're risking political suicide if they violate their vow.
Indiana Sen. Dick Lugar was one high-profile and respected Republican lawmaker who went down to defeat in a primary battle with a Tea Party favourite after losing Norquist's support.
That Tea Party candidate, Richard Mourdock, lost on Nov. 6 after making controversial remarks about rape, costing the Republicans an all-but-guaranteed seat in the Senate.