When the Democratic presidential candidates announced their reactions to Thursday’s assassination of Iranian Maj. Gen. Qassem Soleimani in an attack directed by President Donald Trump, Sen. Bernie Sanders’s statement stood out.

Unlike former Vice President Joe Biden, Sen. Elizabeth Warren of Massachusetts or former South Bend, Indiana, Mayor Pete Buttigieg, Sanders denounced Trump’s action unequivocally without commenting on Soleimani’s character.

“Trump promised to end endless wars, but this action puts us on the path to another one,” Sanders declared Thursday.

The senator from Vermont then elaborated Friday in a live-streamed speech in Anamosa, Iowa. He again framed it as a moment of moral gravity akin to the run-up to the Iraq War, not least because so much of the present conflict with Iran stems from the fateful intervention that began in 2003.

“All of that suffering, all of that debt, all of that huge expenditure of money ― for what?” he said, referring to the Iraq War. “It gives me no pleasure to tell you that at this moment we face a similar crossroads fraught with danger. Once again, we must worry about unintended consequences and the impact of unilateral decision-making.”

Stephen Maturen/Getty Images Sen. Bernie Sanders (I-Vt.) speaks in Anamosa, Iowa, on Friday. Before conducting a town hall, Sanders spoke out against the assassination in Baghdad of Iranian Maj. Gen. Qassem Soleimani.

Sanders’s antiwar message hit home with his younger followers, who expressed their support on social media, as well as some unaligned progressive activists, such as Justice Democrats communications director Waleed Shahid, who retweeted Sanders’s remarks.

The resonance of Sanders’s stance reflects the prominent role of the more dovish, younger voters who make up the core of his coalition.

“Younger generations, including young American Jews, increasingly recognize that the primary threats to average Americans are not foreign bogeymen thousands of miles from our borders but rather the domestic policies that threaten their ability to get an education, earn a living and raise a family,” said Erik Sperling, a spokesperson for the left-wing group Just Foreign Policy.

Indeed, Sanders implicitly acknowledged on Friday the way foreign policy interacts with his signature issue of ending economic inequality.

“It is rarely the children of the billionaire class who face the agony of reckless foreign policy ― it is the children of working families,” he said in Iowa.

But the mere prominence of a figure like Sanders ― and the rush by Warren to catch up to him with a stronger statement Friday ― speaks to just how much the spectrum of acceptable foreign policy discussion has shifted to the left since former President Barack Obama won the Democratic presidential nomination on the strength of his opposition to the Iraq War.

In the early 2000s, Sanders ― now a strong contender for the Democratic presidential nod ― and the small number of his colleagues in the House and Senate who opposed the Iraq War were generally seen as fringe gadflies. It was a time when an MSNBC host could get fired for speaking out against the war. Then-President George W. Bush would win reelection after the war’s stated justification had been exposed as a farce, in part by casting aspersions on the patriotism of his Democratic opponent. That opponent, then-Sen. John Kerry of Massachusetts, could do nothing more than summon objections to the war’s execution, having voted for it himself.

There were echoes of Kerry in various moderate Democrats’ demands for “answers” about Trump’s planning and gripes about whom Trump had failed to notify.

For the activist left, however, no response more complicated than “No war with Iran” would do ― a primal cry against the sophistry that had seduced previous generations of liberals.

“The fundamental question is: Do you believe that the 18-year War on Terror has been a success or a failure?” said Rep. Ro Khanna (D-Calif.), a co-chair of Sanders’s campaign. “I believe and many progressives believe it has been a failure.”

“If killing bad guys were the way to peace, Iraq and Afghanistan would be like Switzerland,” Khanna added.

Many of the voters sympathetic to Sanders grew up in the wake of the Sept. 11, 2001, terrorist attacks when hyper-nationalist sentiment silenced skepticism about the case for invading Iraq, a majority-Shiite Muslim nation on Iran’s border. Some young adults who will be eligible to vote in the November presidential elections were not even born at the start of the invasion of Afghanistan, which the public has also turned against.

The Sanders approach ... clearly has crossover appeal with those conservative Americans who want a limited role for government. Erik Sperling, Just Foreign Policy

What’s more, the flourishing of grassroots opposition to the Iraq War in particular gave birth to a progressive infrastructure that still forms the nucleus of antiwar activism. The rise of MoveOn.org and other online fundraising-driven groups, along with alternative media outlets such as Daily Kos and HuffPost, helped close the resource and messaging gap, albeit modestly, between progressive activists and their counterparts on the right. It’s a network of groups, news outlets and vehicles for activism that allowed the left to coordinate an effective response to Trump’s bellicose rhetoric toward North Korea in August 2017, according to David Karpf, a George Washington University media professor and author of “The MoveOn Effect: The Unexpected Transformation of American Political Advocacy.”

“I remember noticing at the time how a really robust progressive infrastructure ― groups like MoveOn.org and the entire network of Netroots groups came together and said, ‘We are going to come together to stop the U.S. from going to war,’” Karpf said, though he noted that given the sudden nature of events this time, the response has necessarily been a bit more staggered.

But the United States’ seemingly “endless wars” in the Middle East ― as Sanders and other skeptics have come to dub them ― have not just soured liberal Democrats decisively against foreign military adventures. Solid majorities of U.S. military veterans, who have historically leaned conservative, now believe that the two invasions were a mistake, according to Pew polling released in July.

In some ways, Trump’s very election was a sign of a bipartisan decline in appetite for military adventures ― though perhaps not hawkishness of all kinds. As a presidential candidate, Trump touted his opposition to the Iraq War, claiming inaccurately that he had opposed it from the beginning; took a less interventionist posture toward Syria than Democratic presidential nominee Hillary Clinton; and decried the vast sums of money that the U.S. had expended on wars in the Middle East.

For some progressives, that raises hopes of a bipartisan, antiwar coalition with a figure like Sanders at the helm.

“The Sanders approach ... clearly has crossover appeal with those conservative Americans who want a limited role for government,” Sperling said. “Many conservatives are increasingly vocal about how continuing endless wars and maintaining hundreds of thousands of troops abroad at over 800 foreign military bases runs counter to traditional conservative values.”

Spencer Platt/Getty Images As a presidential candidate in 2016, Donald Trump, right, denounced the Iraq War, mocking former President George W. Bush and his brother, then-Florida Gov. Jeb Bush, left.

Events since Trump has taken office, however, have cast doubt on the staying power of such a coalition. When it came to the Iran nuclear agreement, Trump’s desire to roll back Obama’s achievement overcame any anti-interventionist instincts that he might have had. Tearing up that agreement, which international agencies agreed Iran was complying with, helped lead the U.S. to where it is now. But Trump’s popularity remains sky-high with Republican voters.

Matt Grossmann, a political scientist at Michigan State University, says that it is a mistake to even identify Trump’s “America First” foreign policy as anti-interventionist, so much as it is self-interested. Given the way the Trump administration has framed Soleimani as a murderer and imminent threat to American lives, killing him is likely to be seen by Republicans as a consistent feature of Trumpism, he argued.

“The foreign policy attitude of the Republican base is: ‘American interests in the world are good,’” Grossmann said. “It’s broad enough that it can encompass the Trump foreign policy as well as the Bush foreign policy.”

And, of course, Sanders ― or Warren ― still needs to win over Democratic voters and stakeholders before they can test the broader public’s receptivity to an iconoclastic foreign policy vision.

The early signs are not promising. Under the leadership of Speaker Nancy Pelosi of California, House Democrats agreed to a defense spending bill that did not include amendments that would have deprived Trump of the legal basis for military conflict with Iran.

And in the contest for the Democratic presidential nod, Biden currently leads Sanders and Warren by over 30 percentage points in terms of the Democratic voters who say he is the best suited to handle foreign policy.

Sanders could upset the establishment as antiwar candidate Obama did in 2008 or fizzle like the youth-focused antiwar crusader Howard Dean did in 2004, according to Grossmann.

On paper, the candidate already more trusted on foreign policy stands to benefit from an increase in that issue’s “salience,” but Sanders’s “clarity” against Trump has its own strengths, Grossmann said.

Referring to Biden and Sanders, he added, “Both of those candidates have some potential, but they’re already the ones leading the polls, so it’s possible that it’s already baked in.”