WASHINGTON (AP) — A bipartisan Senate deal intended to curb illegal crossings at the U.S. border with Mexico faced almost certain defeat Tuesday as Senate Republicans signaled their opposition, stranding President Joe Biden with no clear way to advance aid for Ukraine through Congress.

The Democratic president has urged lawmakers to embrace a bipartisan Senate deal that pairs border enforcement measures with $60 billion in wartime aid for Ukraine, as well as tens of billions of dollars more for Israel, other U.S. allies in Asia, the U.S. immigration system and humanitarian aid for civilians in Gaza and Ukraine. But he and the Senate’s top Democrat, Sen. Chuck Schumer, and top Republican, Sen. Mitch McConnell, have run into a wall of opposition from conservatives — led by Donald Trump — who rejected the border proposal as insufficient.

Schumer, from New York, cast Tuesday as a “gloomy day here in the United States Senate” during a floor speech in which he scolded Republicans for backing away from the deal. He offered to delay a key test vote on the package until Thursday, but dared them to vote against border security — an issue they have long championed.

“After months of good faith negotiations, after months of giving Republicans many of the things they asked for, Leader McConnell and the Republican conference are ready to kill the national security supplemental package even with border provisions they so fervently demand,” Schumer said.

The White House has worked for months with senators on the carefully negotiated compromise in hopes that it would unlock Republican votes for the Ukraine aid in the House — where scores of GOP lawmakers have come out against funding Kyiv’s fight against Russia. The impasse threatens a cornerstone of Biden foreign policy: Halting Russian President Vladimir Putin’s advance into Europe.

But the Pentagon is sending no more arms shipments to Kyiv just as the war — entering its third year — reaches a critical juncture. Ukraine is struggling with ammunition and personnel shortages while Russia is on the offensive, mounting relentless attacks.

McConnell, a Kentucky Republican, said in a floor speech that it was essential to assert American strength in Europe, the Middle East and Asia, yet also blamed Biden for not responding sooner to threats from rival powers.

“Either we confront challenges we face with clear strategy and firm resolve or we lose,” McConnell said. He made no mention of the need for border security — a piece of the supplemental package that he last year insisted on including.

Facing the prospect of Republicans voting against the package en masse, McConnell recommended to GOP senators on Monday they vote against the first procedural vote, according to two people familiar with the meeting who were not authorized to talk publicly about it and spoke anonymously.

The longtime Republican leader has not been able to convince his conference to warm to the compromises on border security after Trump, the likely Republican presidential nominee, has excoriated it. Even GOP senators who had been supportive of the border policies under discussion came out against the bill on Tuesday.

“After reviewing the bill text, there are provisions that are highly problematic, especially considering the fact that President Biden and Secretary Mayorkas caused this border crisis and have refused to use existing laws already on the books to address it,” Sen. Thom Tillis, a North Carolina Republican who had been involved in the talks, said in a statement.

The package faces even greater resistance in the Republican-controlled House, where House Speaker Mike Johnson, has declared it “dead on arrival.” The Republican Speaker has also left any support for Ukraine aid in doubt.

When asked about wartime aid for Ukraine and Israel, he told reporters Tuesday, “We have to deal with these measures and these issues independently and separately.”

The House was scheduled to vote on a $17.6 billion package of military aid for Israel, but hardline conservatives have signaled opposition because the funding would not be offset with budget cuts in other areas.

House Democratic leaders also said they would not support the bill for Israel. In a letter to Democrats, House Democratic Leader Hakeem Jeffries, along with Reps. Katherine Clark and Pete Aguilar, said the bill was not being offered “in good faith” and urged Democrats to hold out for a package that addresses Ukraine and allies in Asia.

“It is a nakedly obvious and cynical attempt by MAGA extremists to undermine the possibility of a comprehensive, bipartisan funding package that addresses America’s national security challenges in the Middle East, Ukraine, the Indo-Pacific region and throughout the world,” they said.