The Senate votes to avert shutdown after Schumer relents.

The action came just hours before a midnight deadline to avoid a lapse in funding.

The spending debate inflamed intraparty tensions among Democrats that have simmered for weeks about how to mount the most effective resistance to President Trump at a time when he is taking full advantage of his governing trifecta — control of the White House, Senate and House — to trample on congressional power, slashing federal funding and firing government workers with little regard for the guardrails that normally constrain the executive branch.

Mr. Schumer’s abrupt decision to reverse himself and allow the spending legislation to advance stunned many of his colleagues and angered many Democratic lawmakers and progressive activists who were spoiling for a shutdown fight to show their determination to counter Mr. Trump. Many in his party vociferously opposed the temporary spending measure, arguing that it was a capitulation to the president that would supercharge his efforts, and those of his billionaire ally Elon Musk, to defund and dismantle broad swaths of the government.

As recently as Wednesday, Mr. Schumer was arguing strongly against the bill and proposing a monthlong alternative to allow Congress to reach an agreement on individual spending measures with specific instructions over how federal funding should be doled out.

But he reversed course on Thursday after Republicans rejected a shorter-term stopgap bill, with a shutdown looming and amid concerns that Democrats would be blamed.

Recognizing that Democrats were left with only an up-or-down alternative, Mr. Schumer argued that a shutdown would only play into the hands of Mr. Trump and Mr. Musk, ceding more power to them to commandeer federal agencies. In a shutdown, he said, the Trump administration could decide which federal workers would be deemed “nonessential” and furloughed. And he warned that Republicans would have little incentive to reopen the government.

“As bad as the C.R. is,” Mr. Schumer said on Friday morning, using shorthand for continuing resolution, “I believe that allowing President Trump to take more power is a far worse option.”

Democrats joining Mr. Schumer in voting to move it forward included several members of his leadership team — Senators Dick Durbin of Illinois, Brian Schatz of Hawaii and Catherine Cortez Masto of Nevada — and two who have announced their plans to retire: Senators Gary Peters of Michigan and Jeanne Shaheen of New Hampshire. Democratic Senators John Fetterman of Pennsylvania, Kirsten Gillibrand of New York and Maggie Hassan of New Hampshire also voted yes, as did Senator Angus King, the Maine independent who caucuses with their party.

Ms. Shaheen and Mr. King also voted for final passage. Senator Rand Paul of Kentucky was the sole Republican to oppose it.

“Today’s vote on the continuing resolution was a difficult and close call, but ultimately, I made the determination that a flawed bill was better than no bill at all,” Mr. Schatz said in a statement. “A shutdown would enable Donald Trump and Elon Musk to unilaterally determine that the vast majority of federal workers are not essential. And given the number of federal workers in Hawaii, mass furloughs would be deeply painful for people across the state.”

The Republican stopgap legislation would largely keep federal funds flowing at levels set during the Biden administration, but would increase spending for the military by $6 billion. It would not include funds for any earmarks for projects in lawmakers’ districts or states, saving roughly $13 billion.

It also would effectively slash the District of Columbia’s budget by roughly $1 billion over the next six months. But as part of Mr. Schumer’s agreement with Republicans to allow the bill to move forward, the Senate was set to consider a separate measure that would reverse that cut, which local leaders had warned would force dramatic cuts to essential services.

What most concerns Democrats is that the stopgap measure does not contain the specific congressional instructions to allocate money for programs usually included in spending bills. Top Democrats, including Senator Patty Murray of Washington, the party’s lead appropriator, have warned that the lack of explicit directions would essentially create slush funds for the Trump administration at a time when it has already disregarded spending directives set by Congress.

“We have already seen how far President Trump, Elon Musk, and Russ Vought are willing to twist — and outright break — our laws to suit their will,” Ms. Murray said, referring to Russell Vought, Mr. Trump’s budget director. “But House Republicans are setting them up to make everything so far look like child’s play.”

The measure’s Democratic opponents included senators from across the ideological spectrum. A number of centrists voted against the measure, as well as those facing tough re-election contests next year.

The intraparty divide over the measure boiled down to a dispute among Democrats about which of two bad outcomes would be worse for the country. Mr. Schumer and those who voted to allow the spending patch to move forward argued that failing to do so would cause a shutdown that would give Mr. Trump maximum latitude to fund or defund whatever parts of government he saw fit to. But those who refused to said funding the government while the president was making

Senator Jon Ossoff of Georgia, who will face voters next year, said in a statement that he was against the legislation in part because it failed “to impose any constraints on the reckless and out-of-control Trump administration.”

“Both parties in Congress must fulfill our Constitutional obligation to check the president,” Mr. Ossoff said.

Senator John Thune, the South Dakota Republican and majority leader, blamed Mr. Schumer and Democrats for the funding predicament Congress found itself in because of a failure to push annual spending bills through while the Senate was under Democratic control last year.

“To be clear, Republicans aren’t thrilled about another C.R.,” Mr. Thune said Friday before the vote. “But it is our best option to make sure that last year’s failure by Democrats doesn’t interfere with this year’s appropriations process.”

He pledged to make the annual spending bills a priority to try to avert a similar pileup next year.

Rubio said on social media last month that he would not attend the meeting of top diplomats from the Group of 20 nations in South Africa, criticizing the South African hosts for having a focus of the meeting be on “solidarity, equality and sustainability.” Other countries did not follow Rubio’s boycott. China sent its top foreign policy official, Wang Yi, who held meetings with counterparts from other countries while Rubio was absent.

That amendment was defeated in a 47 to 53 party-line vote, falling far short of the 60-vote threshold needed for passage.

The second amendment to be considered and rejected was a measure from Senator Tammy Duckworth, Democrat of Illinois, that would reinstate all veterans who were fired from their jobs as part of the Trump administration’s purge of federal employees. It was defeated in another 47 to 53 vote.