WASHINGTON — Speaker John Boehner on Thursday accepted a two-month extension of the payroll tax cut, succumbing to mounting pressure from the White House, congressional Democrats and fellow Republicans to reverse his House leadership’s opposition to the Senate-passed proposal.

President Barack Obama immediately congratulated congressional leaders on the deal, while Senate Republican leader Mitch McConnell — who increased the pressure on Boehner earlier in the day with a call for such an agreement — said it was a “sigh of relief” for American taxpayers.

Under the deal, the payroll tax assessed American workers will remain at the current 4.2 percent rate instead of reverting to the 6.2 percent rate before the cut enacted last year. Without congressional action, the higher rate would have returned on Jan. 1, meaning an average $1,000 tax increase for 160 million Americans.

The deal also includes the addition of legislative language to ease the administrative burden on small businesses implementing the plan, and a commitment to negotiations on a one-year extension of the payroll tax cut as well as other benefits, according to statements by congressional leaders and Obama.

“We will ask the House and Senate to approve this agreement by unanimous consent before Christmas,” Boehner said, indicating the chambers could pass the plan without objection so that members don’t have to return to Washington from their holiday recess.

However, it was unclear if his Republican caucus would accept the agreement without objection. A GOP uprising during a caucus conference call Saturday had caused Boehner to reject the plan the Senate passed last week with strong bipartisan support, setting up this week’s political showdown in the final days before the payroll tax cut expired.

GOP sources said another conference call Thursday involved Boehner describing the terms of the agreement without allowing any members to ask questions or raise objections. One Republican House member on the call described Boehner “tired and ticked off.”

Boehner, R-Ohio, then announced the deal to reporters, calling the House GOP’s prior opposition to the Senate plan the right thing to do, even if politically questionable.

“It may not have been politically the smartest thing in the world,” Boehner said, but the end result was “we were able to fix what came out of the Senate.”

The speaker also acknowledged the pressure he was under, saying: “I talked to enough members over the last 24 hours who say we don’t like the two-month extension and if you can get this fixed, why not do the right thing for the American people even if it’s not exactly what we want.”

Analysts said Boehner had little choice but to back down.

“It became increasingly obvious he had to fold,” said CNN Senior Political Analyst David Gergen, using poker terminology. Boehner was under “intense pressure from senior Republicans” over a situation that “became so botched,” Gergen said.

Darrell West, the vice president and director of governance studies at the Brookings Institution, said the the issue has worked in the favor of Democrats because they had Republicans “seemingly willing to accept a tax increase” by opposing the Senate extension of the payroll tax cut.

“Any time you can get the other party in opposition to its own stated principles, that’s a good thing,” West said.

The ongoing impasse pitting the House Republican leadership against the White House, congressional Democrats and fellow Republicans was the kind of political gamesmanship that Americans dislike about Congress, Obama said earlier Thursday.

The two-month Senate compromise was passed last Saturday by an 89-10 vote, with strong Republican support, after Senate negotiators were unable to agree on a one-year extension.

Boehner instead demanded negotiations on a one-year extension, arguing that anything shorter would simply prolong the issue and causes uncertainty for American taxpayers and businesses.

His stance drew sharp criticism this week, including an editorial in the conservative Wall Street Journal that said House Republicans had lost the political advantage of advocating tax cuts to Obama and the Democrats.

On Thursday, McConnell’s words and calls by other conservative Republicans for the House to accept a short-term extension showed the tide turning against Boehner and his GOP leaders.

In addition to urging for House approval, McConnell pushed Senate Majority Leader Harry Reid, D-Nev., to appoint conferees to a House-Senate conference committee to iron out differences over a one-year extension — something requested by House Republicans.

“House Republicans sensibly want greater certainty about the duration of these provisions, while Senate Democrats want more time to negotiate the terms,” McConnell said in a written statement. “These goals are not mutually exclusive. We can and should do both.”

McConnell and Reid spoke later Thursday, according to a Senate source.

Meanwhile, conservative Sen. Mike Johanns, R-Neb., and Rep. Sean Duffy, R-Wis., added their voices to GOP calls for House Republicans to relent in their standoff.

“Leader McConnell was right to ask Senator Reid to appoint conferees, and the House should pass the Senate compromise while we continue searching for a resolution by February,” Johanns said in a statement, while Duffy said he would support anything to avoid a Jan. 1 tax hike.

“While I would prefer a year-long tax holiday, I refuse to let anyone play games with my constituents who stand to face a significant tax hike if we don’t act,” Duffy said in a statement. “That’s why I will support any option to extend the payroll tax cut.”

Boehner continued to reject the calls for the House to approve the Senate plan, telling reporters Thursday morning that “we can do better.”

“It’s time for us to sit down and have a serious negotiation and solve this problem,” he said .

Obama reiterated the Democratic position in a phone call with Boehner Thursday morning, stating that the House should pass the Senate’s two-month extension and then negotiators should get to work on a longer-term deal.

The president also met with a group of middle-class Americans as part of a White House attempt to illustrate the impact on 160 million American workers if the tax holiday ends Dec. 31. The typical worker’s take home salary will shrink by about $40 per pay period without the tax cut, or $1,000 annually.

“It’s time for the House to listen … to the voices all across the country and reconsider,” Obama said. “I am ready to sign that (Senate) compromise into law the second it lands on my desk.”

Obama blamed the impasse on “a faction of House Republicans” that refused to support the Senate compromise, even though leaders of both parties had insisted they wanted to extend the payroll tax cut.

He prompted laughter by adding: “Has this place become so dysfunctional that even when people agree to things we can’t do it? It doesn’t make any sense.”

Reid, reinforcing Obama’s stance, released a statement promising that he will be “happy to restart the negotiating process to forge a year-long extension” as soon as the House passes the Senate’s compromise plan.

Many in the GOP fear the issue is damaging the party’s anti-tax reputation heading into the 2012 campaign.

Pushed by his conservative, tea party-infused House GOP caucus, Boehner had continued to insist that anything short of an immediate 12-month extension of the tax holiday would only create more economic instability and do little to generate job growth.

Also at stake: extended emergency federal unemployment benefits and the so-called “doc fix,” a delay in scheduled pay cuts to Medicare physicians.

Both of those measures, along with the tax holiday, were currently scheduled to expire in nine days.

All top Democrats and Republicans publicly agreed on the need for a one-year extension, but critics of the House GOP’s stance insisted that the Senate’s two-month extension was necessary to give negotiators more time to hammer out a deal over how to pay for the continuation.

They accused House Republicans of creating the very instability they had railed against, and of needlessly creating yet another congressional crisis at the end of a year filled with Capitol Hill showdowns.

Sen. John McCain of Arizona, the GOP’s 2008 presidential nominee, strongly criticized the House GOP’s stance on CNN’s “American Morning” Thursday.

“The Republicans are losing this fight. We need to get back on track,” McCain said. “A thousand dollars a year is a big amount of money to most Americans, and I think it’s very important. … I worry about the fact that we are continuing to increase the debt and the deficit, but now it’s become very symbolic, and I think it has to be done.”

A Wall Street Journal editorial Wednesday blasted Boehner and his House GOP colleagues, arguing that they had “achieved the small miracle of letting Mr. Obama position himself as an election-year tax cutter.”

“At this stage, Republicans would do best to cut their losses and find a way to extend the payroll holiday quickly,” the paper’s editorial writers said.

A Senate GOP leadership aide told CNN Wednesday that House Republicans had “painted themselves into a corner.”

“This is a lose-lose situation for us. (House Republicans) let the Democrats get the messaging advantage and, more specifically, we’ve turned one of our key issues on its head,” the aide said. “The Republicans look like they are the ones blocking tax relief.”

“When you are arguing process, you are losing, by definition,” the aide added. “We are arguing process while they’ve got politics on their side.”

Despite mounting pressure on House Republicans to give in and pass the $33 billion Senate bill, a well-placed House GOP source had indicated Wednesday that his side would not consider an end-game to the standoff until next week, just days before the Dec. 31 deadline.

Numerous Senate Republicans have indicated they felt politically undercut by their House colleagues after agreeing to the two-month compromise negotiated by McConnell and Reid.

The House GOP caucus, however, revolted against that blueprint, calling it an inadequate patchwork plan. On Tuesday, the House voted 229-193 on a virtual party-line basis to express its disagreement with the Senate bill and call for the creation of a House-Senate conference committee to resolve the matter — something previously ruled out by Reid.

The House also approved a separate resolution supporting a year-long extension of both the payroll tax cut and emergency unemployment benefits, along with a new, two-year doc fix.

Further complicating matters was the fact that the Senate had adjourned for the year. Most House members also left Washington after Tuesday’s vote.

A number of Republicans have said the party should have declared victory after winning an agreement by Obama — as part of the payroll tax cut package — to make a decision within the next 60 days on whether to proceed with the proposed Keystone XL oil pipeline from Canada to the Gulf of Mexico. Republicans and some Democratic union leaders say the controversial pipeline will create thousands of new jobs; critics question its environmental impact.

A failure to act could have had major political fallout. Numerous observers believe Obama is preparing to parrot Harry Truman’s 1948 campaign next year by running against an unpopular, dysfunctional Congress controlled partly by the GOP.

— CNN’s Ted Barrett, Dana Bash, Kate Bolduan, Lisa Desjardins, Matt Hoye, Xuan Thai, Brianna Keilar and Deirdre Walsh contributed to this report.