In a crushing blow to Speaker John A. Boehner, GOP leaders were forced to pull his “plan B” tax measure from the floor at the eleventh hour as it became clear his conference would refuse to support it.

Unable to bring his fellow Republicans along on a measure that would allow tax rates to rise on millionaires, and with Democrats vowing to block the bill, the Ohio Republican issued a statement Thursday night pushing responsibility to find the way forward squarely on to President Barack Obama and Senate Majority Leader Harry Reid of Nevada.

“The House did not take up the tax measure today because it did not have sufficient support from our members to pass. Now it is up to the president to work with Senator Reid on legislation to avert the fiscal cliff,” Boehner said in a statement. “The House has already passed legislation to stop all of the January 1 tax rate increases and replace the sequester with responsible spending cuts that will begin to address our nation’s crippling debt. The Senate must now act.”

Boehner called a last-minute Republican Conference meeting at 7:45 p.m. on Thursday, and by 8 p.m., the conference had broken. Some lawmakers were only just arriving when the meeting broke up. Republicans afterward said that the mood in the room was somber and the news was met with disbelief.

Boehner led the Pledge of Allegiance and a prayer, then simply said that there were not enough votes to pass the bill, there would be no further votes before Christmas and that he would give a statement to the press on Friday. A few lawmakers clapped in appreciation. Others were surprised.

“Anytime that they call a meeting like this, there’s something that’s out of the ordinary,” Rep. Scott Rigell, R-Va., said. “So I knew that they were having trouble with the vote count, but I had just assumed that they’d be in here, to say, ‘Look, rally, let’s go.’ But that did not happen, of course.”

Boehner exited the Capitol at 8:04 p.m. Swarmed by reporters as he swiftly walked through the doors, he said nothing.

Rep. Steven C. LaTourette, R-Ohio, said Boehner told him that he would call Obama to see about the way forward. But it is clear that his negotiating leverage is tarnished and Republicans may inevitably have to swallow a fiscal cliff deal that heavily skews toward the president’s demands.

“It weakens the entire Republican Party, the Republican majority. It’s the continuing dumbing-down of the Republican Party and we are going to be seen more and more as a bunch of extremists that can’t even get a majority of our own people to support policies that we’re putting forward,” LaTourette said.

But he predicted that, ultimately, the ordeal will not cost Boehner his job, blaming instead the intractable wing of the conference who refused to vote for the plan B.

“It’s like saying that the superintendent of an insane asylum should be discharged because he couldn’t control the crazy people. That’s nuts,” he said.

Rep. Joe L. Barton, R-Texas, said Boehner tried his best but just wasn’t up to the “Herculean” task of selling Republicans on the bill, given the circumstances.

“Our leadership team did the very best they could. It was just too big a hill to climb. And they admitted it,” Barton said.

But outgoing Rep. Cliff Stearns, R-Fla., said Boehner could have tried harder.

“Well, I think that if he felt strongly, he should have just kept us here all night long and just continue to make the case. It was a major issue for him,” he said.

Rep. John Fleming, R-La., said the stiff resistance from Democrats made voting for the bill less appealing.

“I mean, Harry Reid’s already said if we pass this bill tonight, he’s not going to take it up. And the president would veto it anyway. So what’s the point, folks?” Fleming asked.

Democrats sought to press their own position in the wake of Boehner’s surrender on his plan B.

“Plan B has just become plan C, which is chaos,” Rep. Steve Israel, D-N.Y., chairman of the Democratic Congressional Campaign Committee, said in an interview after the announcement.

Israel expressed disappointment that the lawmakers were being directed to go home. “We should now take up the president’s compromise, tweak it, let Republicans try to tweak it so we can get it passed and get the middle class the certainty they deserve,” he said.

Jonathan Strong, Meredith Shiner and Sam Goldfarb contributed to this report.