For the second time in a month, Republicans find themselves deeply divided over one of the most pressing pieces of unfinished business facing the 112th Congress: a measure that would extend the payroll tax holiday for 160 million Americans as well as renew unemployment benefits and prevent a cut in Medicare reimbursement rates.

House Speaker John Boehner (R-Ohio) and Senate Minority Leader Mitch McConnell (R-Ky.). (Reuters/Jonathan Ernst)

Now, Senate Republicans are pitted against House Republicans in a showdown over House Speaker John Boehner’s (R-Ohio) announcement that his conference expects to reject the tax compromise negotiated by McConnell and Senate Majority Leader Harry Reid (D-Nev.) when it comes to the floor Monday night.

As of early Monday evening, four Senate Republicans who are up for re-election next year – Sens. Scott Brown (Mass.), Richard Lugar (Ind.), Dean Heller (Nev.) and Olympia Snowe (Maine) – had called on the House to pass the McConnell-Reid deal.

“There is no question we need to extend the payroll tax cut and unemployment insurance for the entire year,” said Heller, who introduced Senate Republicans’ original payroll tax package. “The American people deserve long-term, forward-thinking policies. However, there is no reason to hold up the short-term extension while a more comprehensive deal is being worked out. What is playing out in Washington, D.C. this week is about political leverage, not about what’s good for the American people.”

Lugar, Brown and Heller are expected to face challenging races next year, a sign that some vulnerable incumbents believe the House’s uprising against the Senate-passed deal amounts to risky political business.

The opposition from Senate Republicans comes as House GOP lawmakers are doubling down on their opposition to the McConnell-Reid plan.

At a news conference with nine other House GOP freshmen, Rep. Cory Gardner (R-Colo.) blasted the two-month Senate plan as “kicking the can down the road.”

“You can’t kick it anymore; the doggone thing’s worn out!” Gardner said.

He later added: “We gave them a great hand to play with. And the United States Senate turns around and plays Solitaire.”

Rep. Tom Reed (R-N.Y.) maintained that House Republicans “will stay here as long as it takes to do what’s right.”

And Rep. Ann Marie Buerkle (R-N.Y.) told reporters that “what (the Senate) sent us over was an insult to the American people.”

House Democrats, seizing on the eleventh-hour dissention, had an explanation at the ready for the apparent GOP disarray.

“We are witnessing the concluding convulsion of confrontation and obstruction in the most unproductive, tea-party-dominated, partisan session of the Congresses in which I have participated,” House Minority Whip Steny Hoyer (D-Md.) told reporters Monday night at his weekly briefing.

While the current discord is likely to leave an impression on voters, what’s most likely to linger on their minds is how – and also whether -- the payroll tax debate is resolved.

As The Fix’s Chris Cillizza notes, House Republicans are taking a gamble by moving to reject the Senate-passed package, as recent polls suggest that the blame will be born more by the GOP than by Democrats if Congress fails to pass any deal at all.

On the other hand, in making their case against the Senate-passed package, the House Republican freshmen who led Monday’s news conference took aim at a target that’s likely to garner them some support among the public as well: the old-school Washington way of doing business.

If House Republicans are able to succeed in securing a longer-term deal – and that’s a big “if” – it would mean that they could claim victory on two fronts. First, they would be able to avoid a repeat in February of a payroll tax fight that has deeply divided their party on policy grounds; and second, they would be able to argue that the GOP conference, led by a hard-charging freshman class, succeeded in rejecting the kind of short-term dealmaking that typically occurs on Capitol Hill.

(It’s worth noting, of course, that many Republicans – even those now pushing for a longer-term extension -- have said they believe it’s bad policy to extend the payroll tax holiday.)

A successful effort by House GOP lawmakers also could give Republicans an argument that they might use to appeal to independents at the ballot box in 2012 – namely, that the GOP must re-take the Senate next year in order to gain further victories in changing Washington.

If the House Republican effort is futile and the chamber eventually (and reluctantly) passes the McConnell-Reid deal, then the greatest political fallout is likely to happen not outside the Beltway but within the GOP conference, where Boehner and other GOP leaders will have to deal with an 89-member freshman class that appears even more emboldened than when its members first arrived in Washington one year ago.

There would also be considerable fallout for McConnell, who would have negotiated and rounded up the support of his conference for a compromise that was ultimately rejected by the House.

Rep. Steve Womack, a first-term Republican from Arkansas, summed up the perspective of House Republican freshmen after Monday’s news conference.

“I think this is a battle-tested freshman class that’s probably been through more issues in their first year than any freshman class than I can recall in memory. ... We went through a budget discussion, a CR [continuing resolution] debate multiple times, threatened government shutdowns, a debt ceiling increase that now takes us to over $15 trillion,” he said.

“Then you have the supercommittee ... and now, we’re trying to do something as simple as keeping a payroll tax from going up two percent on 160 million Americans,” he continued. “This is the kind of thing that will battle-test and harden a member of the freshman class. So they’re performing more like sophomores now than freshmen, I think.”