Democrats celebrated the much-delayed Senate passage of their healthcare and climate spending package, expressing hope that the bill’s approval could improve their prospects in the crucial midterm elections this November.

The bill, formally known as the Inflation Reduction Act, passed the Senate on Sunday in a party-line vote of 51-50, with Vice-President Kamala Harris breaking the tie in the evenly divided chamber.

Raucous applause broke out on the Senate floor after Harris announced the final tally, and Democrats continued their victory lap once the vote had concluded amid a belief that the bill will give Biden – and many Democrats – a record of significant achievement to campaign on.

“I’m really confident that the Inflation Reduction Act will endure as one of the defining feats of the 21st century,” the Senate majority leader, Chuck Schumer, said at a press conference after the bill’s passage. “To do small things with 50 votes is rough. To pass such a major piece of legislation – with only 50 votes, an intransigent Republican minority, a caucus running from Bernie Sanders to Joe Manchin – wow.”

Democrats’ work is not quite done though. The Senate-approved bill now heads to the House, which must pass the legislation before it can go to Joe Biden’s desk. The House is scheduled to return from its recess on Friday to take up the bill, and Democratic leaders have expressed confidence that it will pass.

“The House will return and move swiftly to send this bill to the president’s desk – proudly building a healthier, cleaner, fairer future for all Americans,” the Democratic speaker, Nancy Pelosi, said in a statement.

Democrats hope the bill’s passage could also help them persuade voters to keep them in control of Congress in November, when every House seat and 34 Senate seats will be up for grabs. So far, Democrats’ prospects in the midterm elections have appeared grim, as Republicans are heavily favored to regain control of the House of Representatives.

Asked on Monday morning whether he believed the bill’s approval would benefit Democrats running in November, Biden said, “Do I expect it to help? Yes, I do. It’s going to immediately help.”

Biden pointed to some of the bill’s healthcare provisions, including capping Medicare recipients’ out-of-pocket prescription costs at $2,000 a year, to argue that the legislation would provide concrete assistance to millions of Americans. But that policy will not go into effect until 2025, and Biden acknowledged that some of the bill’s most important provisions will take time to kick in.

That delayed implementation could prove detrimental to Democratic candidates trying to make a pitch to voters about how the party has made the most of its control of the White House and Congress.

Despite its name, the bill is also not expected to provide immediate relief to Americans struggling under the weight of record-high inflation. According to a report issued by Moody’s Analytics, the bill will “modestly reduce inflation over the 10-year budget horizon”.

Republicans accused Democrats of ramming through a partisan bill that failed to address voters’ top concerns, as polls show most Americans believe the economy is getting worse.

“Democrats have proven over and over they simply do not care about middle-class families’ priorities,” the Senate Republican leader, Mitch McConnell, said after the bill’s passage. “They have spent 18 months proving that. They just spent hundreds of billions of dollars to prove it again.”

Republicans’ talking points were echoed by a surprising voice on Sunday: Bernie Sanders. The progressive senator expressed concern that the bill would do little to help working Americans, after he unsuccessfully pushed amendments to the bill that would have expanded its healthcare and financial assistance provisions.

“It’s a very modest step forward,” Sanders told MSNBC. “Bottom line is, I’m going to support the bill because given the crisis of climate change, the environmental community says this is a step forward. It doesn’t go anywhere near as far as it should. It is a step forward.”

Democrats have championed the bill’s environmental provisions, which mark America’s most significant legislative effort yet to address the climate crisis. Experts estimate that the climate policies in the spending package will slash US greenhouse gas emissions by 40% by 2030, compared with 2005 levels. That accomplishment will bring the US within striking distance of Biden’s goal to cut emissions in half by the end of the decade, which scientists say must be achieved to avoid climate disaster.

To win the support of the centrist senator Joe Manchin, the bill also includes controversial proposals to expand oil and gas development on federal lands, which have sparked outcry among some climate activists. But the bill’s defenders say the climate benefits of the legislation far outweigh the costs.

As the spending package moves to the House, Pelosi has the weighty task of keeping her entire caucus in line to ensure the bill’s passage. Given Democrats’ narrow majority in the lower chamber, Pelosi can afford to lose only a few votes and still get the bill passed. It seems like Pelosi will have the votes she needs, after moderates and progressives alike endorsed the package, so Biden could be reaching for his bill-signing pen by the end of the week.