Even though he's never held elected office, he's the man at the center of America's tax debate, vilified by Democrats for his influence over Republicans but admired by conservatives for his unwavering stance against raising new tax revenues.

The average American might not know who Grover Norquist is, but he has been a central power player shaping the spending debate on Capitol Hill over the past three decades.

Today, Norquist, the founder and president of Americans for Tax Reform, met privately on Capitol Hill with Republican members and staff from the House Ways and Means committee, the powerful panel tasked with writing the country's tax policy, and other conservative lawmakers from the Republican Study Committee. As the House prepares to undertake its own version of tax reform next month and Congress braces for the fiscal cliff approaching at the end of the year when multiple provisions of the tax code are set to expire, Norquist worked to unify the GOP.

"Grover can speak for himself as to why he's here," Rep. Steve Scalise, R-La., said following the meeting. "The message about tax policy is that increasing taxes doesn't solve the problem. It actually makes it worse."

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The Americans for Tax Reform pledge commits signers to "oppose any and all efforts to increase the marginal income tax rates for individuals and/or businesses … and oppose any net reduction or elimination of deductions and credits, unless matched dollar for dollar by further reducing tax rates."

"The reason why the pledge is a powerful tool for a candidate or an elected official to share is that it's the same wording" in all races, Norquist said. "If somebody says this congressman or this senator signed the Taxpayer Protection Pledge, you know what they mean."

Asked about Norquist's visit, House Democratic Leader Nancy Pelosi cringed, telling reporters that the anti-tax man does not need to come to the Capitol to exert his influence over Republicans.

"I think they're in touch every day. I think his physical presence here is not any different than the influence that he has on that caucus where he's saying a pledge to me is more important to your pledge to uphold the Constitution of the United States," Pelosi said. "If we're going to take any pledges here other than that, it should be a pledge to uphold our democracy, not to give tax cuts to the richest people in the country, which undermine fairness in our country, destabilizes the middle class, does not create jobs, and increases the deficit."

Norquist dismissed recent criticism of the pledge by prominent Republicans like former Florida Governor Jeb Bush and South Carolina Sen. Lindsey Graham, and pointed out that a majority of Republicans in the House and Senate, along with the GOP's presumptive nominee, Mitt Romney, have all signed the pledge.

"It's not necessary for somebody to sign the pledge to not raise taxes," Norquist said. "[Jeb Bush] is not running for president. Romney is [running] and Romney's made that commitment, so that's sort of a settled question at the national level for Republicans. And, again, you have a strong majority of the Republicans in the House and Senate who have just made sure that we're not going to be raising taxes, and with President Romney he's committed to vetoing any net tax increase."

Asked what he thought about Norquist coming to the Hill to speak with his members, Boehner said he hoped his input would help members coalesce around a solution, and he pointed to the fragile state of the economy as justification not to raise taxes.

"The American people understand that raising taxes in this economy is the wrong thing to do if we're serious about creating jobs," he said. "We're going to outline our principles for tax reform. Listen, I've been around the political process for a long time. I've never voted to raise taxes. But when we've got a big job to do, I'm not interested in raising taxes."