Almost a decade later, the Clinton-Sanders debate is similar. Hillary supports the Iran nuclear deal but insists that it does not herald the beginning of a fundamentally different relationship with the Islamic Republic. In a speech on the agreement last September at the Brookings Institution, she declared that, “This is not the start of some larger diplomatic opening.” In a debate last October she called the Iranians “enemies.”

Sanders, by contrast, sees the nuclear deal as a first step toward “warm relations” between the United States and Iran. He doesn’t articulate the benefits of warmer relations particularly well, but they’re not hard to grasp. When Iran seized British sailors in 2007, it held them for 13 days. After American sailors strayed into Iranian waters earlier this month, Tehran released them after only 15 hours, in large measure because of the goodwill between U.S. Secretary of State John Kerry and Iranian Foreign Minister Javad Zarif, who spoke five times during the crisis.

A warmer relationship between the U.S. and Iran could also improve the chances of a settlement in Syria. Bashar al-Assad’s Sunni opponents cannot remove the Syrian president by force (nor is it clear that America would even want them to). Thus, the best hope for a resolution to Syria’s ghastly civil war is to convince Assad’s patrons, Iran and Russia, that they can ease him out of power in favor of a more legitimate government while retaining some influence in the country. And the better America’s relations are with Iran, the more credible its guarantees about a post-Assad Syria will be.

Granted, that kind of compromise is nowhere in sight, in part because of the militantly anti-Iranian and anti-Shiite policies in vogue among Saudi Arabia’s leaders. But Clinton would bolster Saudi militancy, thus making an agreement in Syria harder. In her speech last fall at Brookings, she pledged to “increase security cooperation with our Gulf allies, including intelligence sharing, military support, and missile defense to ensure they can defend against Iranian aggression.” (Never mind that in Yemen, it’s the Saudis, not the Iranians, who are dropping the bombs.) From her cold-war perspective, Riyadh is America’s ally, Tehran America’s enemy.

Sanders, on the other hand, wants America to use its own rapprochement with Iran to encourage one between Riyadh and Tehran. In his campaign video, Sullivan mocked the Vermont senator for proposing that Iran and Saudi Arabia “join together in a coalition to fight ISIS.” But there are more realistic ways to encourage Saudi-Iranian détente. Last fall, for instance, the Carnegie Endowment for International Peace suggested that the United States push for a new regional security organization for the Persian Gulf—loosely modeled on the Organization for Security and Cooperation in Europe and the Association of Southeast Asian Nations—that includes both Riyadh and Tehran. (Right now, the region’s only security organization, the Gulf Cooperation Council, excludes Iran and Iraq.) Regional-security architecture isn’t sexy, but it’s a way to flesh out the post-cold war vision Sanders is trying to espouse.