But the White House drew a hard line immediately after midnight, saying they would not negotiate over a central issue — immigration — until government funding is restored.
"We will not negotiate the status of unlawful immigrants while Democrats hold our lawful citizens hostage over their reckless demands," White House press secretary Sarah Huckabee Sanders said in a statement. "This is the behavior of obstructionist losers, not legislators. When Democrats start paying our armed forces and first responders we will reopen negotiations on immigration reform."
Both parties confronted major political risks with 10 months to go until the midterm elections. Republicans resolved not to submit to the minority party's demands to negotiate, while Democrats largely unified to use the shutdown deadline to force concessions on numerous issues — including protections for hundreds of thousands of young undocumented immigrants.
The standoff culminated in a late-night Senate vote that failed to clear a 60-vote hurdle, sending congressional leaders and President Trump back to the starting line after days of political posturing on all sides.
"A government shutdown was 100 percent avoidable. Completely avoidable. Now it is imminent," Senate Majority Leader Mitch McConnell (R-Ky.) said on the Senate floor following the vote. "Perhaps across the aisle some of our Democratic colleagues are feeling proud of themselves, but what has their filibuster accomplished? . . . The answer is simple: Their very own government shutdown."
The early contours of the blame game appeared to cut against Trump and the Republicans, who control all levers of government but cannot pass major legislation without at least partial support from Senate Democrats. According to a Washington Post-ABC News poll, Americans said by a 20-point margin that they would blame a shutdown on Trump and the GOP rather than Democrats.
A government shutdown causing employee furloughs has never occurred under unified party control of Congress and the White House. Some furloughs of White House employees began immediately early Saturday.
One possible path out of the impasse appeared in wee hours: Sen. Jeff Flake (R-Ariz.), leaving the Senate floor, said that he had secured an agreement from McConnell to bring a bipartisan bill addressing "dreamers" — young immigrants brought to the United States illegally as children — up for a vote.
Flake said he expected a short-term spending deal to be agreed to during Saturday's Senate session, extending government funding through Feb. 8. By that same date, he said, McConnell would move to bring up the dreamer bill crafted by Sens. Richard J. Durbin (D-Ill.) and Lindsey O. Graham (R-S.C.).
Flake had previously gotten a similar commitment from McConnell, but the majority leader insisted in recent days that any dreamer bill would have to be one Trump supported. Flake said he had urged him, and McConnell had agreed, not to wait on the president.
"At this point, we agree we can't wait for the White House anymore," Flake said.
A McConnell spokeswoman did not immediately comment Saturday morning on Flake's account of a deal.
The midnight drama came after an unusually tranquil day inside the Capitol, where visible tensions remained at a low simmer as various parties undertook quiet talks to discuss ways to avoid the shutdown.
Republicans started the day eager to show a united front: House Speaker Paul D. Ryan (R-Wis.) and McConnell met Friday morning, determined to hold firm to a strategy they had crafted nearly a week prior: Make Democrats an offer they could not refuse by attaching a long-term extension of the Children's Health Insurance Program, or CHIP, as well as the delay of some unpopular health-care taxes. And if they did refuse, the leaders believed, the public backlash would be intense — particularly in states where vulnerable Democratic senators are seeking reelection in November.
McConnell delivered a morning salvo on the Senate floor, declaring that Democrats had been led into a "box canyon" by Senate Minority Leader Charles E. Schumer (D-N.Y.).
But by midday, McConnell's strategy threatened to be upended by Trump — who phoned Schumer and invited him to the White House for a private meeting with no other congressional leaders.
That immediately raised Republicans' suspicions on Capitol Hill that Trump might be tempted to cut a deal with his fellow New Yorker — much as he did in the early stages of a September standoff — that would undercut the GOP negotiating strategy and produce a deal that congressional conservatives could not stomach.
White House aides assured top congressional leaders that no deal would emerge from the meeting, that it was merely meant to gauge the posture of Schumer and the Democrats. Republicans exhaled when that turned out to be so.
Trump and Schumer talked over a cheeseburger lunch, according to a person familiar with their conversations, covering a wide range of contentious issues. Later on the Senate floor, Schumer described a meeting where he forged outlines of a potential deal with Trump, only to see it fall apart once he left the room.
"I reluctantly put the border wall on the table for discussion — even that was not enough to entice the president to finish the deal," he said, adding: "What has transpired since that meeting in the Oval Office is indicative of the entire tumultuous and chaotic process Republicans have engaged in in the negotiations thus far. Even though President Trump seemed to like an outline of a deal in the room, he did not press his party in Congress to accept it."
What ensued for the remainder of the afternoon was a silent standoff, as it became increasingly clear that Republicans would not be able to lure enough Democrats to pass their preferred funding patch.
For a few Democratic senators, a vote to spark a shutdown was too tough to swallow — even for Sen. Doug Jones of Alabama, who faced his first major political dilemma since winning a December special election in a campaign that emphasized his support for CHIP.
"I have made a strong commitment in my state to 150,000 children who need health insurance," he said, announcing his decision to reporters late Friday.
He joined Democratic Sens. Joe Donnelly (Ind.), Joe Manchin III (W.Va.), Heidi Heitkamp (N.D.) and Claire McCaskill (D-Mo.), all of whom face tough paths to reelection in states that supported Trump in 2016 and voted to keep the government open.
But Michigan Sens. Gary Peters and Debbie Stabenow, meanwhile, announced they would both vote against the measure, bolstering the margin opposed to the bill. Four Republicans were also opposed: Sens. Flake, Mike Lee (Utah), Rand Paul (Ky.) and Lindsey O. Graham (S.C.).
Republicans spent much of the day attacking Democrats on several fronts — most frequently by pointing to a litany of critical statements Democratic leaders, including Schumer, had made slamming Republicans ahead of the 2013 shutdown.
In a 2013 ABC News interview, Schumer said, "You know we could do the same thing on immigration . . . We could say, 'We're shutting down the government. We're not going to raise the debt ceiling until you pass immigration reform.' It would be governmental chaos."
"I think the longer it goes on, the more the American people see the hypocrisy on the Democratic side," said Rep. Tom Cole (R-Okla.), a veteran of several shutdown dramas.
Democrats, meanwhile, pointed to other parts of the historical record — notably, a Trump tweet from May: "Our country needs a good 'shutdown' in September to fix mess!"
Conservatives enthusiastically promoted the notion that Democrats were taking the government to the cusp of a shutdown to benefit undocumented immigrants. Democrats want legal status for dreamers in return for a spending agreement. That fight was prompted by Trump's cancellation of the Deferred Action for Childhood Arrivals program, which is expected to take effect in March barring court challenges.
Numerous Republicans said they were perfectly comfortable waging the shutdown fight on those terms, though Democrats have sought to expand the playing field to other issues such as funding to combat opioid abuse and pension bailouts.
"Are Democrats going to shut the government . . . because we want basic reforms and enforcement measures that are going to prevent further flows of illegal immigrants and unskilled immigrants?" said Sen. Tom Cotton (R-Ark.), who is pushing for hard-line immigration policies in return for a DACA fix. "Seems to me like a tough position to win in light of the 2016 election."
Marc Short, Trump's director of legislative affairs, said that the effort by Democrats to put an immigration fix in the spending bill was unreasonable, given that legislative text has not been drafted and the program doesn't expire until March.
"There's no DACA bill to vote on, and there's no emergency on the timing," Short said.
The posturing took place mainly in front of reporters. Missing were the furious back-and-forth negotiations that preceded the 16-day shutdown in 2013, when Republican leaders sought to force a rollback of the Affordable Care Act and met several times with President Obama to seek an accommodation.
Shortly after 6 p.m., Senate Majority Whip John Cornyn (R-Tex.) looked at his watch and vented frustration.
"Government shuts down in what, five hours and 40 minutes? And there's no solution? I don't know whether Senator Schumer is just determined to take it down," he said. "Obviously, we don't want to shut the government down, either, but they seem to be determined to do so."
Visibly, only Graham shuttled back and forth between the Republican and Democratic leadership offices, shopping a proposal to replace the four-week funding extension passed by the House with a slightly shorter one.
As the 10 p.m. vote approached, Cornyn declared: "No deal."
Schumer rejected a proposal that would have extended funding by three weeks, to Feb. 8, instead of four. Schumer floated a 10-day extension, which would have set another deadline just before Trump delivered his State of the Union address on Jan. 30. Shortly after midnight, McConnell closed the vote and declared an impasse.
The Trump administration worked up plans to keep national parks and monuments open despite a shutdown as a way to blunt public anger, and while the military would not cease to operate, troops would not be paid unless Congress specifically authorizes it.
In a sign of the preparations on Capitol Hill, congressional staffers received formal notice Friday morning that they may be furloughed starting at midnight. Individual lawmakers will have to determine which aides must report for work during the impasse.
Trump postponed a scheduled trip to his Florida resort, where he had scheduled a pricey fundraiser to mark his first anniversary in office. Ryan faced the cancellation of an official trip to Iraq, and House Majority Leader Kevin McCarthy (R-Calif.) and other lawmakers revisited plans to travel to Switzerland for the World Economic Forum.
The latter trip drove Democratic attacks earlier in the day, especially after McCarthy floated plans in the morning to send House members home for a planned week-long recess.
"They want to spend next week hobnobbing with their elitist friends instead of honoring their responsibilities to the American people," House Minority Leader Nancy Pelosi (D-Calif) said of Republicans.
Earlier in the night, around 150 protesters gathered outside the Capitol to hear Democrats promise not to back any spending deal that did not grant legal status to DACA recipients.
"This is a movement," said Sen. Kamala D. Harris (D-Calif.). "We're going to have some good days, and we're going to have some bad days. And like every movement that has allowed our country to progress, we are going to have to fight."
Sean Sullivan and John Wagner contributed to this report.