CONCORD, New Hampshire — The conflict between Iran and the United States this week exposed one of the most significant policy differences among the top of the Democratic presidential field, pitting Vermont Sen. Bernie Sanders against former Vice President Joe Biden.

Sanders is a longtime antiwar advocate who voted not to authorize the use of force in Iraq. He’s staked out distinct positions on foreign policy, including America’s relationship with Israel and its role in the Middle East. Biden represents the establishment wing of the party’s views. He chaired the Senate Foreign Relations Committee for years, voted for the Iraq War, and is running on a platform of a return to normalcy.

“Joe Biden voted and helped lead the effort for the war in Iraq, the most dangerous foreign policy blunder in the modern history of this country,” Sanders said in an interview with CNN’s Anderson Cooper Monday night.

Sanders co-introduced a bill late last week to block funding for any military action in Iran and put out a video saying he’s “not sorry” for his long history of opposing US wars. Sanders and fellow progressive candidate Elizabeth Warren (who wasn’t in office for the vote on Iraq) both lead a Wednesday night antiwar strategy call with MoveOn activists. Sanders and Warren also signed on to a bipartisan Senate resolution saying Congress has not yet approved any war with Iran.

Biden played up his faith in the military establishment and his place in the Obama White House, which negotiated the Iran nuclear deal in 2015. As President Trump seemingly blamed Obama in a Wednesday speech, Biden went on the offensive, defending his former boss on Twitter.

“He’s been President for three years,” he said of Trump. “It’s time he stops blaming President Obama for his failures.”

Instead of using his statement today to lay out a coherent strategy on Iran, Donald Trump used it to mislead the country on the Obama-Biden record. He's been President for three years. It's time he stops blaming President Obama for his failures. — Joe Biden (@JoeBiden) January 9, 2020

Speaking at a fundraiser near Philadelphia Tuesday night as initial reports of Iran retaliation came in, Biden also painted Trump as irrational.

“I just pray to God as [Trump] goes through what’s happening, as we speak, that he’s listening to his military commanders for the first time, because so far that has not been the case,” Biden said, per a pool report.

His supporters frequently play up his experience.

“I keep coming back to this steady hand on the tiller. A lot of people just want the daily chaos to stop; they just want to return to normalcy,” said former US Ambassador Terry Shumaker, who co-chaired Bill Clinton’s campaign in 1992 and is now a prominent Biden supporter in New Hampshire. “If I’m assessing the electorate correctly, that candidate is Joe Biden.”

The rest of the Democratic presidential field also criticized Trump for how he’s handled the tumultuous moment.

The situation in Iran is also giving Warren and former South Bend, Indiana, Mayor Pete Buttigieg a moment to burnish their foreign policy credentials. Warren has highlighted her experience on the Senate Armed Services Committee, and has advocated diplomacy in the Middle East over military action. Buttigieg has spoken about his firsthand experience in the Middle East as a former military intelligence officer who served in Afghanistan.

“A presidential candidate who has served has a personal understanding of what we’re dealing with,” Buttigieg told reporters at a campaign stop last week. “I’m not here to say my qualifications are a prerequisite, but I will say that they made me extremely aware of the consequences of the decisions made in the White House Situation Room.”

There are few polls available to test how voters are thinking about Iran and the Democratic primary. But what available polling there is seems good for Biden.

Biden has a long record on foreign policy, and recent polls show the former vice president leading the pack in trust on that issue. A Tuesday HuffPost/YouGov poll found 62 percent of registered voters who identify as Democrats or lean Democratic said they trust Biden on Iran, compared to 47 percent who trust Sanders and Warren and 31 percent who trust Buttigieg.

A November CNN poll (conducted well before the current Iran conflict) showed 48 percent of registered Democrats or Democratic-leaning independents saying Biden could best handle foreign policy, with 14 percent saying Sanders was their top choice to handle the issue.

That could be especially true with foreign policy.

“His experience as vice president, international travel and work, he’s represented the United States,” Londonderry voter and Biden supporter Kathy Bancroft, 68, told Vox, listing the reasons Biden has her vote. “Respect is what we need.”

Biden’s and Sanders’s campaigns have been leaning in on foreign policy for months; one of Biden’s top surrogates is former Secretary of State John Kerry, and the Biden campaign has put out several foreign policy-related campaign ads. Sanders was one of the lead sponsors on a bipartisan bill to end America’s involvement in Saudi Arabia’s war in Yemen, one of the few times the Republican-controlled Senate has rebuked President Trump.

Sanders has also spoken up in support of leftist Latin American leaders including Bolivia’s ousted president Evo Morales, who tweeted his thanks to “hermano @BernieSanders.” It’s a wedge issue that’s separated him from Warren, his fellow progressive in the race — but also from more moderate candidates like Biden.

Sanders’s supporters like his authenticity, and it’s hard to question the Vermont senator’s decades of commitment to keeping the United States out of wars. And he seems to have found an ally in Warren, who has advocated diplomacy and keeping a channel of communication with Iran open, rather than attacking first and cleaning up later.

“I see this as a question of judgment, and my concern about Donald Trump is not just when he took out Soleimani ... it’s the way Donald Trump has handled this from the very beginning,” Warren said Wednesday morning on MSNBC. “Not all problems can be solved militarily, and we should not ask our military to solve problems that they cannot alone solve.”