It has also driven a wedge into what was once considered an ironclad Republican line in the Capitol, where the GOP controls both chambers and the governor's office.
Call it the Norquist effect.
"I don't think the pledge is a bad thing, but the problem is that everything isn't black and white," said Drew Crompton, legal counsel and chief of staff to Senate President Pro Tempore Joe Scarnati (R., Jefferson). "There are issues of gray. And to have an outside organization be the sole determiner on which side a piece of legislation may fall - is it a tax, or not? - is a dangerous precedent."
Corbett signed Norquist's "Taxpayer Protection Pledge" last year, when he and other Republican candidates were riding a national wave of voter discontent with big government spending. The pledge is simple: signers solemnly bind themselves to oppose any and all tax increases.
Thirteen governors (New Jersey's Chris Christie is not on the list) and 1,252 legislators have signed the pledge, according to Americans for Tax Reform. In Congress, 236 House members and 41 senators have signed.
"I would argue it's a spending pledge," says Norquist, 54, who began the group in 1985 and has been a force in national politics. "It limits the amount of money that any government can spend. And if you don't have money, you can't spend what you don't have."
He scoffs at suggestions he or his group has special sway with Corbett or any governor.
"This is a pledge to the people he represents," says Norquist, who adds that he hasn't met with Corbett but has requested a sit-down with him. "The most powerful people in Pennsylvania are the taxpayers of Pennsylvania. To imply anything else is to try to fool people into thinking that the commitment that Corbett and other governors made isn't to the people."
In Pennsylvania, Corbett's participation in the pledge arched some eyebrows, even within his party. Some top Republicans wondered privately and publicly if he wasn't foolishly boxing himself in as the state's deficit soared. Penning a budget without the wiggle room to raise or impose new taxes seemed risky, both politically and policywise. Even more so for a newbie to the policy arena like Corbett, who was state attorney general before becoming governor.
But it has also gained him points. When he unveiled his $27.3 billion budget in March, he received kudos from fiscal conservatives for not spending more than the state was expected to reap in revenues.
To deal with a $4 billion deficit, Corbett proposed the steep cuts in education aid that have forced school administrators to prepare to shed programs and staff. Even in recent weeks, as state revenue began to rise more than anticipated, the governor has not budged.
"It's quite refreshing from a taxpayer's perspective to have a governor say our problem is spending, not revenues," says Matt Brouillette, head of the libertarian Commonwealth Foundation in Harrisburg. "It's driving politicians on both sides of the aisle crazy. And I think that's a good thing."
Indeed, cracks within the GOP began to show soon after Corbett proposed his spending plan. Some Republican legislators have balked at the proposed cuts, even as Democrats rallied to the notion that Corbett was hurting the middle class with his refusal to raise any taxes, even on corporations and drillers.
House Republicans, led by staunch conservative Majority Leader Mike Turzai (R., Allegheny), have said they'd stick to Corbett's $27. 3 billion bottom line, even as they restored some school aid and axed welfare spending. On Monday night the House was preparing to vote on its version of the budget.
But the real test may follow in the Senate, where the leadership is more moderate and the differences with the governor more distinct. GOP senators say they'd like to tap some of that extra revenue flowing into state coffers to offset some proposed cuts.
And, led by Scarnati, they are pushing a "local impact fee" (they stress it's not a tax) on gas drilling. Scarnati has said he can't see enacting a budget without also considering such a fee.
"There are differences between the House and the Senate," says Rep. Curt Schroder (R., Chester). But as the budget's June 30 deadline nears, he says, "I think those things will work themselves out."
The pledge is limiting, but "that is a good thing," he reasons.
"Nobody forced Tom Corbett to sign a no-tax-increase pledge - he did it on his own and went into it with his eyes open," Schroder says. "That is what voters said they wanted. I think it's incumbent on us to help him keep his pledge."
Contact Inquirer staff writer Angela Couloumbis at 717-787-5934 or firstname.lastname@example.org.