Updated at 4:22 p.m. 

The chorus of congressional Republicans showing a willingness to buck Grover Norquist's influential no-tax pledge to avert the "fiscal cliff" is growing. While the moves could be the start of a broader — if temporary — shift in GOP orthodoxy on taxes, the impact of the defections on the "fiscal cliff" negotiations may not end up being so monumental.

Will other House Republicans join Rep. Peter King (R-N.Y.), above, in bucking Grover Norquist? (Andrew Harrer/Bloomberg)

While Republicans have been saying they are willing to close loopholes and cap deductions to raise revenues, so far the GOP side hasn't embraced the idea of raising tax rates on the wealthy — something Democrats have demanded. And with polling showing much of the American public sides with the White House on taxes, there is little incentive for Democrats to capitulate.

In other words, if Republicans continue to follow the lead of the current Norquist defectors, the gap between Democrats and the GOP will narrow but remain far from closed.

Let's start with what the Norquist defectors have said. On Sunday, Sen. Lindsey Graham (R-S.C.) and Rep. Peter King (R-N.Y.) reiterated a willingness to stray from the strict, no-tax-hike posture advocated by the conservative lobbyist. Graham made clear his position was conditional. Democrats have to get serious about entitlement reform, he said. King echoed Sen. Saxby Chambliss (R-Ga.) in suggesting that the Norquist pledge may be out of the step with the nation's present economic condition.

What the Republicans didn't offer was an endorsement of raising tax rates on the wealthy. Nor did Sen. Bob Corker (R-Tenn.), who on Monday became the latest to break with the Norquist pledge. That means they are still at odds with Democrats over a key pillar of the fiscal debate.

"I'm not in favor of tax increases. I'm in favor of significant tax reform 2 lower tax rates & generate additional revenue through job growth," Chambliss, who could face a 2014 primary from former Georgia secretary of state Karen Handel tweeted Monday morning.

Earlier this month, House Speaker John Boehner (R-Ohio) opened the door to accepting new revenue, but reiterated his opposition to raising tax rates on the wealthy because of its impact on job creation. What we are seeing from Graham, King, Corker and Chambliss is comparable. And if enough House Republicans, line up behind them, Boehner would be in position to go to Democrats with a coherent conference willing to talk about increasing revenues.

But even if the majority of congressional Republicans joins the ranks of those willing to budge on taxes, there would still be a divide between the underlying Democratic and Republican approaches to remedying the soon-to-expire tax and looming spending cuts at the center of the "fiscal cliff" debate.

At a recent news conference, President Obama agreed about the necessity of closing tax loopholes. But he also took a strict posture on the need to allow the Bush administration-era cuts in the tax rate of the wealthiest Americans to expire.

"I think that there are loopholes that can be closed, and we should look at how we can make the process of deductions, the filing process easier, simpler. But when it comes to the top 2 percent, what I’m not going to do is to extend further a tax cut for folks who don’t need it, which would cost close to a trillion dollars," Obama said.

House Minority Leader Nancy Pelosi (D-Calif.) echoed the president in her recent remark that any deal must include tax rate increases for top earners. “Just to close loopholes is far too little money," she said.

It's hard to find many reasons for Democrats to cede ground in the debate. For starters, Obama is coming off a reelection win. Secondly, polling shows Democrats have the public on their side when it comes to increasing taxes on the wealthiest Americans. Two out of three Americans said they would prefer to see Obama and Congress come to terms on a budget plan that includes a combination of spending cuts and tax increases on higher-income Americans, according to a CNN/ORC poll released Monday. Only one in three said the plan should include only spending cuts.

What's more, a plurality of Americans (45 percent) said congressional Republicans would be responsible for a failure to reach an agreement by the end of the year, compared to just 34 percent who said Obama would be responsible.

Indeed, we could be witnessing a major shift in the way congressional Republicans navigate the issue of taxes. That point shouldn't be understated. But in terms of the actual impact on the negotiations that will determine the nation's immediate fiscal trajectory? The step isn't quite as big.