Sen. Pat Toomey (R., Pa.), one of the most staunchly conservative members of the Senate when it comes to taxes and spending, said today he would not violate Grover Norquist's "no tax pledge" but also left the door open to increasing revenues.

"I don't intend to violate any pledge," Toomey said on CNN Tuesday morning. "My pledge is not to support higher taxes. What we're faced with in just a few weeks is a massive tax increase. If I can help ensure that we don't have that tax increase, then I believe I've fulfilled my pledge to fight for the lowest possible taxes."

In saying that he's fighting for "the lowest possible taxes," though, Toomey left the door open to some type of added tax revenue, but on a much smaller, more targeted scale than the massive tax hikes scheduled to take effect as part of the fiscal cliff looming at year's end. In fact, long before some Republicans began disavowing their pledges to Norquist to never support tax hikes, Toomey had proposed ways to raise tax revenue without increasing tax rates. He reiterated those ideas on CNN, calling for raising revenues by closing loopholes and eliminating some deductions in exchange for lower marginal tax rates and a simpler tax code – a plan he first outlined in July.

Toomey is an influential fiscal conservatives in the Senate, making his stand one to watch as President Obama and top lawmakers try to negotiate a deal that satisfies both sides but can also pass through both houses of Congress.

UPDATE: His language about the "lowest possible" tax hike hews closely to something the Wall Street Journal wrote in an editorial about Norquist, arguing that "President Obama's re-election means that taxes for upper-income earners are going up one way or another. The Bush rates expire on December 31 unless Mr. Obama signs an extension ... If taxes are going up anyway because the Bush rates expire, and Republicans can stop them from going up as much as they otherwise would, then pledge-takers deserve some credit for that."

Said Toomey: "The concern that I have is that we are now just a few weeks away from a massive tax increase and I am trying to find a way to avoid inflicting that damage on our economy and going through that. So if we're going to have to have some revenue increase, which this president seems determined to do, I would hope that we could at least do it in a way that does the least economic harm." He added, "Then at least you could hope you could have that you'd some pro-growth policies in your tax code that would offset the damage done by greater revenue."

Toomey said any tax hike could damage the economy, but that Obama "seems absolutely determined to inflict a tax increase on the American people." Recognizing that reality, Toomey said he would favor new revenues only if it is accompanied by lower tax rates and reforms to entitlement programs – meaning Social Security, Medicare and Medicaid.

"If we're going to do something on the revenue side, for gosh sakes let's not damage the economy any more than we have to," he said.

Obama has argued that families making more than $250,000 should pay higher taxes to help balance the federal budget, and that taxes should be held steady for incomes below that threshold. He will be taking his case to Montgomery County on Friday.

The White House has been skeptical of plans such as Toomey's that call for raising new revenue solely by closing loopholes.

"I'm not aware of a realistic proposal that reduces deductions and tax expenditures more generally by enough to address our fiscal problems," said Alan Krueger, chairman of Obama's Council of Economic Advisers.

Obama spokesman Jay Carney told reporters Monday that closing loopholes and increased tax rates on income above $250,000 are both needed to raise enough revenue to fairly balance the budget.