As negotiators on Capitol Hill held out hope of a swift agreement that could end the impasse before the weekend was out, the House and the Senate reconvened for a rare Saturday session. The likeliest path to reopening the government was an agreement on a stopgap spending measure that stretched longer than the few days that Senate Democrats wanted, but shorter than the four weeks that the House approved on Thursday night.
But agreeing on the length of the stopgap bill was complicated by several contentious issues, particularly the fate of the hundreds of thousands of young immigrants known as Dreamers.
Mr. Trump spoke at midday with the House speaker, Paul D. Ryan, Republican of Wisconsin, and multiple times with Senator Mitch McConnell, Republican of Kentucky and the majority leader, to strategize on a path forward. But Sarah Huckabee Sanders, the White House press secretary, said the president refused to negotiate on immigration issues until there was a deal to reopen the government.
In his morning Twitter burst, Mr. Trump said Democrats were prioritizing “illegal immigrants” over American citizens and military personnel, and argued that the only solution to end the dysfunction was to defeat the party in this year’s midterm congressional elections.
“Democrats are far more concerned with Illegal Immigrants than they are with our great Military or Safety at our dangerous Southern Border,” the president said. “They could have easily made a deal but decided to play Shutdown politics instead. #WeNeedMoreRepublicansIn18 in order to power through mess!”
In fact, it was Mr. Trump who opted not to accept a deal that he and Senator Chuck Schumer of New York, the top Senate Democrat, had hashed out over lunch at the White House on Friday. Such an agreement would have kept the government open, funded a border wall and extended legal status to undocumented immigrants brought to the United States as children, while including disaster aid funds and money for a federal children’s health insurance program. John F. Kelly, the White House chief of staff, later called Mr. Schumer to say the agreement lacked sufficient immigration restrictions.
While Mr. Schumer said shortly after the government shut down that “in my heart, I thought we might have a deal tonight,” White House officials argued that he had drastically overstated the progress made during the lunch.
On Saturday, though, Mr. Schumer said that even members of the president’s party had by now recognized that Mr. Trump, a professed deal maker, was ill-equipped to strike a political compromise.
“What’s even more frustrating than President Trump’s intransigence is the way he seems amenable to these compromises before completely switching positions and backing off,” he said on the Senate floor. “Negotiating with President Trump is like negotiating with Jell-O.”
One senior administration official, who asked for anonymity to discuss private conversations, described a neophyte president who genuinely wanted to reach a deal with Mr. Schumer when he called the Democratic leader to the White House on Friday. But Mr. Trump had not determined how it would play out or mapped out a strategy with Republican leaders, the official said, nor considered how the politics of a shutdown might unravel.
So on Saturday, the president was left alternately defiant and angry, self-pitying and frustrated. He argued to aides that he did not deserve the blame he was taking — without a credible deal on the table, there was little for him to do.
In the absence of a resolution, Republicans and Democrats traded political recriminations.
“What a massive failure of leadership,” Tom Perez, the chairman of the Democratic National Committee, said in a statement. “Donald Trump, Paul Ryan, Mitch McConnell and Republican lawmakers pulled out all the stops to give a massive tax break to their wealthy donors, but now that it’s time to take care of the rest of America they can’t get their act together.”
“This is Trump’s Republican Party: chaotic, destructive and driven by greed,” he added.
The president’s series of Twitter posts came on a morning when he had planned to be in Palm Beach, most likely preparing for a round of golf and the Saturday night party at Mar-a-Lago, which guests have paid $100,000 per couple to attend. Instead, his schedule was blank, containing no indication that the president was headed south to warmer temperatures or celebratory events.
Mr. Trump was impatient to complete an agreement to reopen the government — whatever the details might be — and depart for his resort, advisers said, but as the day wore on without an agreement, hopes of a return to normalcy began to fade.
Traveling to the Middle East, Vice President Mike Pence sought to reassure American service members that the shutdown would be resolved, telling them, “We’ll get this thing figured out in Washington.” But he told reporters traveling with him, “It’s going to take as long as it takes.”
While the administration has argued that it is doing more than President Barack Obama’s did in 2013 to soften the effect of a shutdown, Mr. Trump and Mr. Pence both emphasized that active-duty military personnel would be serving without pay until the government resumes its normal functions.
“These soldiers deserve better,” Mr. Pence said at Shannon Airport in Ireland, where Air Force Two was refueling as he made his way to Cairo for the start of a three-day visit to the Middle East.
“You have troops headed down range to Kuwait for six months, and they are anxious about the fact that they aren’t going to get paid right away,” he added, calling the situation “unconscionable.”
“It’s disappointing to every American that Democrats in the Senate would shut down the government when we have troops in harm’s way,” Mr. Pence said.
Democrats tried early Saturday to win passage of emergency legislation to ensure that military personnel received pay during the shutdown, but Senator Mitch McConnell of Kentucky, the majority leader, objected. He said he wanted to reach an agreement to fund the entire government “before this becomes necessary.”
In a statement on Saturday, Ms. Sanders said, “The president will not negotiate on immigration reform until Democrats stop playing games and reopen the government.”