An emergency spending bill to provide billions of dollars in new security assistance for Ukraine and Israel was blocked in the US Senate on Wednesday as Republicans pressed their demands for tougher measures to control immigration at the US border with Mexico.

The vote was 49 in favour to 51 against, leaving the $110.5 billion measure short of the 60 votes needed in the 100-member Senate to pave the way to start debate, threatening President Joe Biden’s push to provide new aid before the end of 2023.

The vote was along party lines, with every Senate Republican voting no along with Senator Bernie Sanders, an independent who generally votes with Democrats but had expressed concerns about funding Israel’s “current inhumane military strategy” against Palestinians.

The bill would provide about $50 billion in new security assistance for Ukraine, as well as money for humanitarian and economic aid for the government in Kyiv, plus $14 billion for Israel as it battles Hamas in Gaza.

Senate Majority Leader Chuck Schumer, a Democrat, also voted “no” so that he could introduce the measure again in the future. After the vote, Schumer noted the risks if Ukraine falls, saying it was a “serious moment that will have lasting consequences for the 21st century,” risking the decline of Western democracy.

Republicans said it was essential to make their case for tighter immigration policies and control of the southern border.

“Today’s vote is what it takes for the Democratic leader to recognize that Senate Republicans mean what we say,” Senate Republican Leader Mitch McConnell said in a floor speech earlier on Wednesday. “Then let’s vote. And then let’s finally start meeting America’s national security priorities, including right here at home.”

Even if the bill passes the Senate, it still would need to be approved in the Republican-controlled House of Representatives, where dozens of Republicans have voted against Ukraine aid, including Speaker Mike Johnson.

Congressional Republicans and Democrats have been debating for months how to address Biden’s request for billions of dollars in funding for Ukraine as it fights Russian invaders, for Israel following the Oct. 7 attacks by Islamist Hamas militants, for US interests in the Indo-Pacific, and for international humanitarian relief.

Months-long impasse

The White House’s two requests for Congress to pass spending bills have failed to advance, and tempers have become increasingly frayed on Capitol Hill as the impasse threatens to stretch into 2024. Democrats argue that aid for allies is essential to support global democracy and ward off autocracy.

“Make no mistake, today’s vote is going to be long remembered. History is going to judge harshly those who turned their backs on freedom’s cause,” Biden said in remarks at the White House.

A group of Senate Democrats called a press conference to argue that blocking the bill would send a message to both US adversaries and allies that the United States does not stand with its international partners.

“This is running out. We have but a few days for us to make clear, positive progress toward working out the final details necessary for us to show that the United States is a reliable ally,” Senator Chris Coons said.

Republicans contend that excessive illegal immigration across the southern border with Mexico is a hugely important security concern, and say they want more accountability than they are getting from the Biden administration for US taxpayer funds that go to Ukraine.

The emergency spending bill included $20 billion for border security.

Schumer said on Tuesday he would try to break the impasse by offering Republicans the chance to add an amendment on border policy to the legislation.

No such amendment had been announced by Wednesday evening.