The government shutdown that began on Wednesday reflected a deep partisan divide between Republicans and Democrats over spending and policy priorities.
But when it came time to vote on legislation to extend spending and avert a shutdown, a few members of the Democratic caucus broke with the party to support Republicans’ plan for doing so.
In votes just hours before the shutdown and again on Wednesday after it had begun, Senators Catherine Cortez Masto of Nevada and John Fetterman of Pennsylvania, both Democrats, and Angus King, the Maine independent who caucuses with them, were the only members of the minority to vote for a simple, roughly seven-week funding extension sought by Republicans.
In doing so, they broke with Senator Chuck Schumer, Democrat of New York and the minority leader, who has pressed his party to hold the line against the G.O.P. spending plan until Republicans and President Trump negotiate with Democrats on a compromise that includes health care concessions.
“The American people are suffering, and if they are suffering in my state, they are suffering in Republican states, right?” Ms. Cortez Masto said in an interview. “And that’s what’s going to drive this.”
In a statement Tuesday night before her vote for the Republican plan, she warned that a shutdown would only worsen problems created by Mr. Trump and Republicans in her state.
“That’s why I cannot support a costly shutdown that would hurt Nevada families and hand even more power to this reckless administration,” she said.
In a video on Tuesday evening, Mr. King made a similar argument, citing the president’s threat to take action during a shutdown to conduct mass layoffs and restrict funding for programs he opposes.
“This was a difficult vote,” he said. “The paradox is, by shutting the government, we’re actually giving Donald Trump more power. And that was why I voted yes.”
Republicans signaled that they would keep pressing to peel off more Democrats willing to vote with them in favor of funding the government with no concessions. Vice President JD Vance said he and Mr. Trump were in talks with both Democratic and Republican senators, and had been encouraging G.O.P. senators to lobby their Democratic friends to cave.
The G.O.P. controls 53 seats in the Senate, where 60 votes — including at least seven members of the minority — are needed to advance spending legislation. In this case, Republicans would need eight, since one of their members, Senator Rand Paul of Kentucky, is opposed to a straight funding extension.
“All it takes to reopen the government is cooperation from just five more Senate Democrats,” Senator John Barrasso, Republican of Wyoming and the majority whip, said on Wednesday morning. “We picked up three Democrats last night, so there are clearly cracks on their side of the aisle.”
“That will continue,” he added, projecting further gains.
(Republicans picked up only two members of the minority on Tuesday night; Mr. Fetterman had previously voted for the Republicans’ spending plan and made it clear he would not vote against a proposal to avert a shutdown.)
It is not clear how many more Democratic senators would be willing to break with their party, which appears to feel little incentive, at least for now, to capitulate.
Still, some Democrats have signaled that they are eager to see the stalemate swiftly brought to an end. Senator Jeanne Shaheen of New Hampshire, a centrist who is not seeking re-election next year, said in a statement on Tuesday night that she wanted to “work quickly” to find a bipartisan compromise.
“I have been in intensive conversations with colleagues from both sides of the aisle on how to find a path forward, and I’m eager to work with my Republican colleagues to find common ground,” Ms. Shaheen said.
Senator Gary Peters, Democrat of Michigan, said he was engaged in conversations with Republicans and was eager to find a way out of the gridlock. He said the discussions were “productive” but added that “trust is a problem” when it comes to negotiating with Republicans in both the House and the Senate.
“We’re going to have to deal with that and try to build trust in the process to create a framework that allows people to be confident that the agreements that are made will be kept,” Mr. Peters said.
At the moment, the Republican strategy is to keep voting, over and over, to increase pressure on Democrats to cave while the White House moves to make a shutdown difficult for them through layoffs and denials of funding for their priorities.
Mr. Schumer, however, is betting that outside forces will stiffen the spine of Democrats.
“Americans throughout the country are opening their mailboxes and finding letters in there telling them that their health insurance is about to go way, way, way up,” he said on Wednesday morning. “When Democrats say we want to work with Republicans to lower premiums, to strengthen health care, all we are doing is reflecting what the American people already want. Nothing more, nothing less.”