Joe Biden had hoped to end his first year in office by signing his signature bill, the Build Back Better Act, a $1.75tn spending package that includes massive investments in healthcare, childcare and climate initiatives.

Instead, the president is ending the year with a member of his own party dealing a devastating blow to his legislative agenda and potentially Democrats’ prospects in next year’s midterm elections.

The announcement by centrist West Virginia senator Joe Manchin that he will not support the Build Back Better Act has kicked off a round of fiery recriminations among Democrats, as party leaders rushed to determine whether the bill can still somehow be saved.

But Manchin’s comments did not seem to leave much wiggle room for future negotiations. After announcing his opposition on Fox News Sunday, Manchin released a fuller statement saying the cost of the legislation, which had already been slashed in half to appease him, was too high to justify.

“I have always said, ‘If I can’t go back home and explain it, I can’t vote for it,’” Manchin said. “Despite my best efforts, I cannot explain the sweeping Build Back Better Act in West Virginia and I cannot vote to move forward on this mammoth piece of legislation.”

The White House was clearly blindsided by Manchin’s announcement, accusing the senator of reneging on commitments that he had reiterated to Biden just days earlier.

“On Tuesday of this week, Senator Manchin came to the White House and submitted – to the president, in person, directly – a written outline for a Build Back Better bill that was the same size and scope as the president’s framework, and covered many of the same priorities,” press secretary Jen Psaki said on Sunday.

“If his comments on Fox and written statement indicate an end to that effort, they represent a sudden and inexplicable reversal in his position, and a breach of his commitments to the president and the senator’s colleagues in the House and Senate.”

Despite the significant setback, the White House pledged to keep advocating for the bill’s passage. “The fight for Build Back Better is too important to give up. We will find a way to move forward next year,” Psaki said.

Senate majority leader Chuck Schumer has already said he will hold a vote on the Build Back Better Act once the chamber reconvenes in January.

In a “Dear colleague” letter that singled out Manchin, Schumer said: “Senators should be aware that the Senate will, in fact, consider the Build Back Better Act, very early in the new year so that every member of this body has the opportunity to make their position known on the Senate floor, not just on television.”

But the bill will likely have to undergo significant revisions to win the support of Manchin, and Democrats cannot move forward without him because of the 50-50 split in the Senate.

For the left of the Democratic party, the dilemma represents a bitter case of “I told you so”. The Congressional Progressive Caucus had insisted that the bipartisan infrastructure bill should not pass until the Build Back Better Act could move forward as well. Instead, the House passed the infrastructure bill last month after Biden convinced progressives that he could also secure 50 Senate votes for the spending package.

Despite Biden’s assurances, six progressives still voted against the infrastructure bill to protest the decoupling of the two proposals, and those lawmakers have expressed outrage over Manchin’s announcement, which has proven their predictions correct.

“We have been saying this for weeks that this would happen, and we took the hits,” congresswoman Cori Bush told MSNBC on Sunday. “Having those coupled together was the only leverage we had. And what did the caucus do? We tossed it.”

However, it is not just the left wing of the Democratic party expressing criticism of Manchin. Congresswoman Suzan DelBene, the chair of the centrist New Democrat Coalition, warned that the party would suffer severe consequences if the Build Back Better Act is not passed.

“The challenges our country faces are too big and the cost of inaction is too high to throw in the towel on Build Back Better negotiations now,” DelBene said Sunday. “Failure is not an option.”

In an effort to bring Manchin back to the negotiating table, DelBene suggested that the bill should be altered to focus on funding a smaller number of programs for a longer period of time.

Manchin’s most recent gripe about the legislation is that it calls for some programs to be phased out after a year or a few years. The senator has complained that those programs will inevitably be renewed and result in even more government spending, although the White House has said any future renewals would be paid for through additional revenue-raising provisions.

“At the start of these negotiations many months ago, we called for prioritizing doing a few things well for longer, and we believe that adopting such an approach could open a potential path forward for this legislation,” DelBene said.

But the progressives who are outraged at Biden and Democratic leaders for their handling of the negotiations have endorsed a different tactic, calling on the president to use the power of the executive pen to enact immediate change.

“Biden needs to lean on his executive authority now. He has been delaying and under-utilizing it so far,” New York congresswoman Alexandria Ocasio-Cortez said in a Monday tweet.

“There is an enormous amount he can do on climate, student debt, immigration, cannabis, healthcare, and more. Time is running out. We need to move and use alternative paths.”

Biden’s strategy in the coming weeks will likely have significant repercussions on the midterm elections. If Democrats cannot deliver on their promises to address the climate crisis and make childcare and healthcare more affordable, despite having full control of Congress and the White House, they will face many angry voters as they seek reelection next year. After months of drawn-out negotiations and no results to show for them, those voters may decide they are ready for a change in Washington.