Democratic Senator Joe Manchin of West Virginia said Sunday he would oppose his party’s $2 trillion Build Back Better bill, effectively killing the centrepiece of President Joe Biden’s ambitious plan to reassert US global leadership on climate.

“I cannot vote to continue with this piece of legislation, I just can’t,” Manchin said on Fox News Sunday. “I tried everything possible.”

With Democrats and Republicans, who oppose the mammoth bill, each holding 50 seats in the Senate, Manchin, a political moderate, is a swing vote in position to decide whether it can pass. The House of Representatives narrowly approved it last month.

Manchin’s decision drew a searing response from the White House with press secretary Jen Psaki accusing him of reneging on his recent promises to work with administration officials to hammer out a compromise deal that both sides could support in the bill’s final language.

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

Biden, who had personally lobbied Manchin over several months to get him on board, was notably silent.

The House version would have funded about $555bn to drive decarbonisation mostly in the power and transport sectors, the biggest sources of US greenhouse gas emissions. This is more than six times the $90bn in the 2009 economic stimulus law, the first targeted action by Congress to address climate change at the urging of former President Barack Obama.

A key aspect of this bill is to create new federal tax credits for battery storage, clean energy manufacturing, and transmission development, while extending and making those for solar more lucrative for project sponsors that meet certain domestic content and labour requirements.

According to the White House, the bill would have significantly advanced the country toward Biden’s four core 2030 climate-related targets: a 50-52% reduction from 2005 levels in economy-wide net emissions, which is compatible with the Paris Agreement; an 80% decline in utility sector emissions; installation of 30GW offshore wind capacity, and electric vehicles to comprise half of all US automobile sales.

Why Manchin said ‘no’

Manchin has had strong reservations about the bill since early this summer when it began to take shape in the House after having been initially proposed with a $3.5trn price tag. Biden agreed to downsize it on several occasions in an effort to win political support from moderate Democratic lawmakers.

In a separate statement, Manchin said the Build Back Better Act, its formal name, which also seeks to revamp the country’s education, healthcare, immigration, and tax laws, would “dramatically reshape our society in a way that leaves our country even more vulnerable to the threats we face”.

The bill would cost more than twice what its supporters claim, he said, citing the non-partisan Congressional Budget Office, and this would further balloon the nation’s $29trn national debt.

The nation’s debt load could pose limitations to the nation’s ability to “quickly and effectively respond” to the highest inflation in 39 years, rapidly spreading Covid-19 Omicron variant and increasing geopolitical uncertainty as tensions rise with both Russia and China.

Manchin, who represents the second largest coal-producing state, also said the bill was trying to do too much, too fast with clean energy, and this would risk electric grid reliability and increase US dependence on foreign supply chains.

“We have invested billions of dollars into clean energy technologies so we can continue to lead the world in reducing emissions through innovation,” he said, adding that to do so “at a rate that is faster than technology or markets allow will have catastrophic consequences for the American people”.

Manchin cited as examples California and Texas, the two leading renewable energy states, who suffered major grid failures in the last several years. California because of premature retirement of natural gas plants and wildfires, and Texas from a February freeze.

What’s next?

Manchin left the door open to continue negotiations with Democrats and Biden on a much smaller bill but said he will “do so in a way that does not risk our nation’s independence, security, and way of life.”

Seething with anger over Manchin short-circuiting their climate and social safety net legislative ambitions, members of the party’s ascendant left wing in Congress were in no mood to further compromise with him.

This leaves Biden in a weakened position as he looks to salvage something from the most important part of his domestic agenda and retain credibility overseas with his climate pledges.

A smaller version of Build Back Better, if there is one, could fail to win backing from either Manchin or enough progressive Democrats and could consume months of further political wrangling that would distract Biden from a range of pressing issues at home and overseas.

On the other hand, Democrats could try and pass less ambitious legislation to give lawmakers something to tout in November 2022 mid-term elections as they face voters angry and anxious over Covid-19, inflation, rising urban crime and other hot-button issues.