The amendment, introduced by Republican Rep. Thomas Massie of Kentucky, was rejected by a 314-104 vote during consideration of a broader national security spending bill.

While the measure failed, the support it received from 104 Democratic lawmakers marked the strongest congressional challenge yet to long-standing bipartisan backing for Israel.

The vote exposed a widening split among Democrats ahead of this year’s US midterm elections, with progressive lawmakers increasingly distancing themselves from Israeli Prime Minister Benjamin Netanyahu’s handling of the war in Gaza.

Most Republicans voted against the proposal, preserving the military aid package.

House Democratic Leader Hakeem Jeffries opposed the amendment but acknowledged that US policy toward the Middle East should change.

In a letter to colleagues before a private caucus meeting, Jeffries said a shift in American policy was necessary “for the good of Israel and the Palestinian people,” while arguing there were more effective ways to influence Netanyahu’s government than eliminating military assistance.

The issue has become a growing source of tension within the Democratic Party, as progressive lawmakers and left-wing activists push for a tougher stance on Israel, while more centrist Democrats continue to support the long-standing US-Israel alliance.

Democratic Whip Katherine Clark of Massachusetts joined supporters of the amendment, underscoring divisions within the party’s leadership.

Republicans have sought to capitalise on the split, portraying Democrats as increasingly influenced by the party’s progressive wing.

Members of the Republican Party also differ over foreign aid, with some of President Donald Trump’s allies pushing to scale back US military spending abroad.

The debate has come at a time when public opinion on the Gaza war is increasingly shifting, adding further pressure on lawmakers from both sides of the divide.

According to a recent AP-NORC poll, around one-third of US adults, including roughly half of Democrats, believe Israel has committed genocide against Palestinians during the Gaza war — an allegation strongly rejected by both Israel and the US government.

During debate on the House floor, Massie argued that the $3.3 billion earmarked for Israel should instead be directed toward domestic priorities, including infrastructure and veterans’ services, citing rising US budget deficits.

He also criticised the use of American-supplied weapons in the conflict, saying civilians had often been caught in the fighting.

“I think we should stop it — we should put them on a diet,” Massie said.

Opposing the amendment, Democratic Rep. Steny Hoyer of Maryland warned that ending military assistance would undermine US national security and weaken efforts to counter anti-Israel groups such as Hamas and Hezbollah, which he said pose threats to American citizens and military personnel.

Outside Congress, advocacy groups also lobbied lawmakers ahead of the vote.

The pro-Israel lobbying organisation AIPAC urged members of Congress to reject the amendment, describing it as dangerous.

Meanwhile, the progressive advocacy group J Street opposed the proposal but said it understood why many Democrats supported it as a way to register opposition to the Israeli government’s conduct in Gaza and other regional conflicts.

J Street President Jeremy Ben-Ami said the broader consensus among Democrats remained support for the security and rights of both Israelis and Palestinians, despite differences over the amendment.