The Senate minority leader, Chuck Schumer, said on Thursday he would vote for a Republican-written bill to fund federal agencies through September and avert a government shutdown.

Schumer’s comments suggest that his members are prepared to provide the necessary votes to clear a procedural hurdle ahead, allowing the seven-month spending measure to advance to a final vote.

In a floor speech, Schumer called the vote a “Hobson’s choice” for Senate Democrats, under pressure from their counterparts in the House and their activist base to block the House-passed measure that they have argued would give Donald Trump too much discretion over spending decisions. But after days of tense, closed-door meetings, Schumer said he ultimately believed a shutdown, which would begin Friday at midnight, would carry “consequences for America that are much, much worse”.

He said a shutdown would give Trump and Musk “carte blanche to destroy vital government services at a significantly faster rate than they can right now”.

“Under a shutdown, the Trump administration would have full authority to deem whole agencies, programs and personnel non-essential, furloughing staff with no promise that would ever be rehired,” Schumer said, expanding on his rationale a day after signalling his party was prepared to withhold their votes in a bid to force Republicans back to the negotiating table.

Senate Republicans hold a narrow 53-seat majority, well shy of the 60-vote threshold needed to advance the legislation. Senator Rand Paul, a staunch fiscal hawk, has indicated his opposition to the House bill, meaning eight Democrats would likely need to support the bill for it to overcome procedural hurdles to reach a final vote in the chamber.

The 99-page House-passed measure provides a $6bn boost to military budgets while carving out $13bn from non-defense spending – which Democrats say amounts to an assault on critical programs for vulnerable Americans.

From the annual House Democratic caucus retreat in Leesburg, Virginia, House Democrats had urged their Senate counterparts to oppose the bill. All but one House Democrat voted against it on Tuesday.

All week, Senate Democrats have wrestled publicly and privately over their vote. Republicans ramped up their attacks, warning that Democrats would be to blame for an unpopular government shutdown even though the GOP holds a governing trifecta in Washington. The Democratic senator John Fetterman, of Pennsylvania, previously announced his support for the bill, while Senator Ruben Gallego, Democrat of Arizona, said on Thursday he would vote against it.

“Let’s not kid ourselves: this is a bad resolution that gives Elon Musk and his cronies permission to continue cutting veterans’ benefits, slashes resources for Arizona’s water needs, and abandons our wildland firefighters,” Gallego said in a statement. “I can’t stand by that.”

Progressive activists quickly denounced the move by Schumer, urging Democrats not to follow his lead and “surrender” to Trump and the Republicans.

“This is a weak [strategic] move driven by fear and learned helplessness,” Ezra Levin, the co-founder and co-executive director of Indivisible, which has led many of the anti-Trump and anti-Musk protests. “Don’t follow him. He’s leading the party into irrelevance and helping Trump and Musk in the process.”