As the Israel-Gaza war raged, President Joe Biden made clear to Israeli Prime Minister Benjamin Netanyahu that there was a problem.

Full-throated support for Israel among Democrats was waning, namely because of progressives. Among the clearest signs were moves in the House and Senate to block a $735 million weapons sale to Israel, a deal that only weeks earlier Democratic congressional aides said they hadn’t considered controversial or even noteworthy.

On May 19, about nine days into the conflict, Biden told Netanyahu that unless he wanted to risk losing bipartisan support for Israel in Congress, he “expected” the Israeli premier to wind down the fight. The next day, Israel and Hamas agreed to a ceasefire.

Progressives in and out of government say their actions both pressured Biden and gave him a convincing talking point in conversations with Netanyahu. “Progressives deserve a little credit for the ceasefire,” said Ben Rhodes, a former top national security aide to President Barack Obama and an outspoken advocate for a more progressive foreign policy. “Biden was looking over his left shoulder and told Netanyahu, ‘You have to move on this.’”

The true extent to which progressives directly played a role in ending this round of Israeli-Palestinian fighting is unclear. The administration insists no members of Congress changed Biden’s mind during the conflict, and the president openly stated last week that “my party still supports Israel.”

But what is clear is that progressives no longer play a fringe role in the American national security discussion. They’re a real force, and their time is now.

“Looking at where this debate was 10 or even five years ago and where it is now, I think we can’t help but be encouraged,” said Matt Duss, Sen. Bernie Sanders’s national security adviser and a leading figure of the progressive foreign policy movement.

Biden’s presidency gave progressives a clear opportunity

Progressives have made their voices heard on foreign policy throughout US history. From the Wilsonian era to the Vietnam and Iraq wars, they’ve long pressured American leaders to avoid conflicts abroad and focus on economic and social issues at home.

The current progressive movement upholds those ideas and also places primacy on tackling climate change and promoting human rights while curbing support for authoritarian regimes.

The problem is that it didn’t have much success swaying either the Obama or Trump administrations.

Obama didn’t end the war in Afghanistan, for example, and supported Israel’s bombing campaign during the previous Israel-Hamas fight in 2014. “I think that undercut us with respect to human rights, and it didn’t help us make any progress on the Israeli-Palestinian issue,” Rhodes told me.

And though President Donald Trump shared some of the antiwar tendencies of progressives, namely not initiating long wars in the Middle East, he ignored all left-leaning advice while cozying up to dictators, minimizing human rights, calling climate change a “hoax,” and exacerbating racial tensions at home.

But progressives did achieve one moral victory with Trump in office. After years of trying and failing, in 2019 Congress passed a resolution, spearheaded by progressives such as Sanders and Rep. Ro Khanna (D-CA), to end US support for the Saudi-led war in Yemen, though Trump vetoed it. Still, it proved progressives could have a serious impact on the broader national security debate.

“The Yemen success was important and it gave momentum to the whole movement,” said Tommy Vietor, a former Obama White House official and now co-host with Rhodes of the left-leaning foreign policy podcast Pod Save the World.

Biden’s rise, though, was a boon to the progressive foreign policy movement.

Since the campaign, Biden’s team has remained closely connected to progressive climate, veteran, and other groups to hear their views on myriad national security issues. They’ve helped influence some of the president’s decisions, such as ending most offensive support for the Yemen war, withdrawing all US troops and contractors from Afghanistan by September 11, treating climate change as the top global threat, and waiving intellectual property protections for US-made Covid-19 vaccines.

That’s not to say the president is pursuing a purely progressive foreign policy, or that progressives are entirely pleased with him. “The left thinks it’s getting a raw deal from Biden on foreign policy generally,” said Van Jackson, a former Obama-era Pentagon official now at the Victoria University of Wellington in New Zealand. That perception, he said, has to do with Biden tying domestic issues to competition with China and resisting making deep cuts to defense spending.

Still, Jackson acknowledges, “there is a greater opportunity to influence policy from the left than any time since I’ve been alive.”

But privately, progressives share their concern that their wins so far came in areas where Biden already agreed with them. On the campaign trail, Biden said he would end “forever wars” and focus his attention on motivating the world to confront climate change.

The real test would be when progressives and Biden differed on a major issue. Then came the Israel-Gaza war.

The progressive pushback on Israel proved their staying power

Following weeks of aggressive and at times violent Israeli actions toward Palestinians in Jerusalem, the militant group Hamas launched rockets at Israel on May 10. Israel responded with devastating airstrikes and artillery fire on the group’s positions in Gaza.

The disparity between the two sides — Hamas has thousands of imprecise rockets while Israel has one of the world’s strongest militaries and most effective missile defense systems — meant it wasn’t a fair fight. Before a ceasefire ended the nearly two weeks of fighting, Israel had killed nearly 250 Palestinians, including 66 children, while Hamas had killed 12 Israelis, including two children.

Biden, as he has throughout his career, backed Israel’s “right to defend itself” while initially saying very little about the plight of the Palestinians. Progressives countered the president, saying support for Israel could and should be coupled with defending Palestinian rights.

Among the most vocal critics was Rep. Rashida Tlaib (D-MI), the first Palestinian American woman to serve in Congress. On May 13, she gave an impassioned speech on the House floor about the suffering of Palestinians in Gaza and the West Bank and why the US should reconsider its unconditional support of Israel.

“When I see the images and videos of destruction and death in Palestine, all I hear are the children screaming from pure fear and terror,” she said, holding back tears. A statement from a Palestinian mother she read about putting her kids to bed during the bombings “broke me a little more because … my country’s policies and funding will deny this mother’s right to see her own children live without fear and to grow old without painful trauma and violence.”