In the days since President Donald Trump ordered the assassination of Iranian Maj. Gen. Qassim Suleimani, leading Democratic presidential candidates have condemned the escalation and sought to differentiate themselves on the issue of foreign policy. The Suleimani strike brought the U.S. and Iran to the brink of war, but the incident was preceded by years of Trump’s efforts to ratchet up tensions. He pushed new sanctions to undermine President Barack Obama’s Iran nuclear deal — which had dramatically dimmed the likelihood of a confrontation — and, eventually, followed through on a campaign promise to back out of it entirely. The history of Iran sanctions — both during Trump’s administration and Obama’s — as well as the maneuvering over the nuclear deal as it came into focus and was eventually signed, offer a rich history of 2020 candidates’ credentials for dealing with Iran.

Sanders has often led the way against conflict with Iran — frequently as a lonely yet strikingly consistent voice in the early years of the Trump administration.

Sen. Bernie Sanders, I-Vt., who’s currently surging in polls across early primary states, has used the foreign policy debate over Iran as an opportunity to highlight his staunch anti-war record, while drawing sharp contrasts between himself and former Vice President Joe Biden, an enthusiastic backer of the disastrous Iraq War. In the aftermath of the strike that killed Suleimani, Sanders co-introduced a bill to block funding for any military action in Iran. He also released a video saying that he’s “not sorry” for his opposition to past U.S. wars, from the Vietnam War when he was a young man to voting against the 2003 invasion of Iraq. “If you think the war in Iraq was a disaster,” he warned in the video, “my guess is that the war in Iran would be even worse.” Another 2020 contender, Sen. Elizabeth Warren, D-Mass., joined Sanders’s bill, and every candidate in the Democratic presidential contest issued statements that cast the strike as reckless. As more facts emerged about the killing, other candidates also began questioning the legal justification for the strike — which Sanders had strongly denounced as an “assassination” out of the gate. The united Democratic response of skepticism and alarm at Trump’s Suleimani strike was remarkable for a caucus that has so frequently been fractured over Iran policy. Even many of the 2020 contenders have gone back and forth on Iran issues. Yet Sanders has often led the way against conflict with Iran — frequently as a lonely yet strikingly consistent voice in the early years of the Trump administration. Fight Over 2017 Iran Sanctions As Trump has been pushing aggressive policies toward Iran since entering office, establishment Democrats in Congress helped pave the way through their consistent support for sanctions on the country.

In 2017, new sanctions spearheaded by the Trump administration began making their way through Congress. Out of all the candidates from congress on the January 2020 debate stage who served during this period, Sanders was the only one in either the Senate or House to defend the nuclear deal by consistently voting against the new measures. In contrast, other candidates in this cycle, like Sens. Amy Klobuchar of Minnesota and Michael Bennet of Colorado, joined Republicans to co-sponsor the new sanctions despite Iranian leadership’s repeated warnings that expanding sanctions would constitute a violation of the deal. (New Jersey’s Sen. Cory Booker, who officially dropped out of the presidential race on Monday morning, co-sponsored the legislation as well.) Sanders’s dovish positioning became clear well before the final vote on the bill. Shortly before an early vote to move the bill forward in the Senate, a terrorist attack on the Iranian parliament killed 12 people and left more than 40 injured. Sanders called for delaying the vote to debate the measure on account of the attack. “On a day when Iran has been attacked by ISIS, by terrorism, now is not the time to go forward with legislation calling for sanctions against Iran,” he said on the Senate floor. “Let us be aware and cognizant that earlier today, the people of Iran suffered a horrific terror attack in their capital, Tehran.” Yet all but five of the Senate’s Democrats — including current 2020 rivals Klobuchar, Bennet, and Warren — bucked Sanders and voted to move debate forward. The Vermont senator ended up being the only current Democratic presidential hopeful to vote against moving forward. The Only No Vote in the Caucus The original codification of the Iran deal also provides ample history to examine candidates’ records. Biden, for his part, played a critical role as vice president in persuading congressional Democrats to support the deal. The Obama White House tapped him to lead the lobbying effort on the Hill, to make sure the votes were there to prevent Congress from blocking the deal. Jeffrey Prescott, a former deputy national security adviser to Biden, co-authored an op-ed as the 2017 sanctions gained momentum saying that they gave “Iran an excuse to undermine the deal.” And another Obama administration veteran, former Secretary of State John Kerry, who negotiated the nuclear deal, came out publicly calling the new sanctions “dangerous.” Yet Biden himself was nowhere to be found.

When it came down to a vote on the 2017 bill in the full Senate, Sanders would be the only current 2020 contender to vote against it.