The prospects for passing legislation to speed military aid to Ukraine this year are fading, as Republicans balk at striking a quick deal on immigration policy changes they have demanded in exchange for allowing the bill to move forward.
After a weekend of intensive bipartisan border talks yielded progress but no breakthrough, Senator Chuck Schumer, Democrat of New York and the majority leader, acknowledged on Monday that negotiators were still far from completing a deal.
“It’s going to take some more time to get it done,” he said on the Senate floor on Monday afternoon, laying out plans for the week that made no mention of any votes on the aid package for Ukraine.
That was a reversal from last week, when Mr. Schumer announced he would delay the Senate’s holiday break and keep the chamber in Washington this week, in hopes of reviving and passing the Ukraine aid bill before leaving for the year.
Republicans have let it be known they have no intention of dropping their objections by then.
“We feel like we’re being jammed,” Senator Lindsey Graham, Republican of South Carolina, said on NBC’s “Meet the Press” on Sunday. “We’re not anywhere close to a deal. It’ll go into next year.”
Senate negotiators, who since last week have been meeting daily with White House officials and Alejandro Mayorkas, the homeland security secretary, to hash out a way forward, said they had resolved some disputes over enhanced border enforcement measures.
But without a full agreement to show to senators, a vote remained a long way off.
“There’s nothing for senators to look at yet,” Senator Christopher S. Murphy, Democrat of Connecticut, said of the negotiations on Monday night, later adding, “You’ve got to get it right, not get it fast.”
Negotiators plan to meet with White House officials again on Tuesday and have said they would keep talking for as long as it took to resolve outstanding issues. But Republicans have warned Mr. Schumer against trying to rush negotiations or squeeze their side into a last-minute vote on a bill that has yet to materialize.
“We do need to be aware of the fact that this is not just an exercise in the Senate,” Senator John Cornyn, Republican of Texas, said on “Fox News Sunday.” “It’s not just the Senate and the president agreeing to something. It’s something that can actually pass the House and be signed into law.”
Only 17 of the 49 G.O.P. senators returned to Washington on Monday night for votes on nominations, signaling skepticism among Republicans about the chances of securing a border deal in time for a vote before the holidays.
On Sunday, Senator Ron Johnson, Republican of Wisconsin and one of the no-shows, circulated a letter signed by 14 of his colleagues calling on his party’s leaders to hold a special meeting, no earlier than Jan. 8, on the details of the border talks.
“Rushed and secret negotiations with Democrats who want an open border and who caused the current crisis will not secure the border,” they wrote.
At the same time, factions of both parties are rebelling over the direction of the negotiations. In recent days, senators and administration officials appear to have coalesced around raising the standard for migrants to claim that they can credibly fear persecution if returned to their home countries.
Negotiators have also found common ground on the idea of expanding the administration’s ability to quickly deport migrants who unlawfully cross into the United States. The authority would kick in once the number of crossings rises above officials’ capacity to detain and process migrants.
They are still at odds, however, on issues such as which migrants should be held in detention or allowed into the country on parole to await their court appearances.
The areas of emerging agreement have angered progressive Democrats and Hispanic lawmakers, who have warned White House officials against reviving Trump-era border policies Mr. Biden previously rejected.
Mr. Mayorkas and Jeffrey D. Zients, the White House chief of staff, promised leaders of the Congressional Hispanic Caucus in a virtual call on Saturday that they would keep them better apprised about the border talks. But members of the caucus said they were still incensed about the range of restrictive policies the administration had been willing to entertain, according to people familiar with the private meeting who discussed it on the condition of anonymity.
On the other end of the political spectrum, conservative Republicans have also resisted any potential deal with Democrats, arguing that their party should make no concessions and instead insist on passage of the more restrictive House-passed border enforcement bill. That legislation, which has no chance of getting through the Democratic-led Senate, prioritizes resuming construction of a wall at the U.S. border with Mexico, resurrecting Trump-era policies of keeping migrants either in detention facilities or in Mexico, and ending group-based parole policies that have allowed migrants from countries like Afghanistan and Ukraine to take refuge temporarily in the United States.
The House is not due back in Washington until the week of Jan. 8, and Speaker Mike Johnson has given no indication that he would be willing to call members back into session, even if senators and administration officials are able to strike a deal in the next few days.
That has made proponents of a deal reluctant to discuss the elements of any potential compromise, lest it be picked apart and criticized over the holidays.
Kayla Guo contributed reporting.