Iran has been a critical player in the Syrian war since 2011, crafting a complex foreign policy and military strategy to preserve its Syrian ally. What have been the drivers of Iranian decision-making in this conflict? And how has Iranian strategy evolved over the course of the war? This article argues that the logic of deterrence has been fundamental not just for shaping the contours of Iran–Syria relations since the Islamic Revolution of 1979, but also for determining the overall trajectory of Iranian strategy in the Syrian war. The authors outline Iran's decision-making calculus and divide the country's strategy on Syria after the Arab Spring into four primary phases: 1) a ‘Basij’ strategy to establish local militias in Syria; 2) a regionalization strategy to incorporate transnational fighters and militias in the war effort; 3) an internationalization strategy to incorporate Russia and balance the United States; and 4) a post-ISIS deterrence strategy to balance against the United States, Turkey and Israel. Iran's Syria strategy progressively escalated in response to the possible defeat of its ally and the deterioration of its forward deterrence capacities against the United States and Israel. Today, the potential for direct inter-state conflict is rising as proxy warfare declines and Iran attempts to maintain the credibility of its forward deterrence.

Interview with Hassan Ahmadian, a Postdoctoral Research Fellow at the Iran Project, Harvard Kennedy School Belfer Center for Science and International Affairs, to discuss topics such as the role of the U.S. in Syria and broadly in the MENA region; identity issues; and the role of Iran and the future of the nuclear deal.

Events in the Middle East tend to have serious policy implications for the United States given the range of important U.S. economic, political, counterterrorism, and broader military interests in the region. Although there is a healthy debate to be had about where the Middle East might fit into a potential recalibration or rebalancing of U.S. global priorities, at this juncture I don’t believe it would be in U.S. interests to turn its back on the region’s crises and just hope for the best. 

Although there are a number of major disagreements between Iran, Russia and Turkey, what is important in the end is that they are all opposing the current US policies in Syria. All three countries have suffered from US sanctions and all have serious trust issues with the Trump administration. Emphasising this common ground, Iran's Supreme Leader Ayatollah Ali Khamenei told Russian President Vladimir Putin earlier in September that "the US is containable" and that Iran and Russia should continue close cooperation towards this goal. Whichever strategy Iran chooses to pursue, the US will likely feel the pressure on the ground soon enough. That could end up being an effective deterrent against US plans of opening additional fronts against Iran in the Middle East.

Having been targeted indirectly by the “leading from behind” policy under President Obama, Iran is now faced with a more organized US effort under Trump to establish a regional setting — an "Arab NATO," the Middle East Strategic Alliance (MESA) — that is supposed to “push back” against Iran. Against this backdrop, however, Iran does not seem worried about US efforts to create MESA. In fact, Washington’s new anti-Iran campaign in the Middle East and beyond is interpreted as falling within the “milking logic” of the Trump administration.

While many Shia movements may have differences of opinion with Iran, as long as the Trump presidency uncritically supports Saudi Arabia and the threat of military conflict with Iran remains on the horizon, it is unlikely that any popular Shia group will side with the United States. The administration’s narrow focus on Iran will provoke precisely what the Trump White House aims to prevent—a more cohesive regional Shia movement under Iran’s protection and aggrieved Shia supportive of countering U.S. influence in the region. In other words, the current U.S. course is narrowing policy discussions both within individual Shia organizations as well as across transnational Shia alliances by closing the door to pro-U.S. policy alternatives. This further consolidates Iran's position as the center of the Shia world and its long-standing partnership with various Shia transnational movements throughout the Middle East such as the Lebanese Hezbollah, many of Iraq's Popular Mobilization Forces (PMF), and Yemen's Ansarallah (the Houthis) all of whom are engaged in critical regional hotspots.

In 2006, in the midst of a fierce war between Israel and the Lebanese militant group Hezbollah, former U.S. Secretary of State Condoleezza Rice famously stated that the world was witnessing the “birth pangs of a new Middle East.” She was right—but not in the sense she had hoped. Instead of disempowering Hezbollah and its sponsor, Iran, the war only augmented the strength and prestige of what is known as the “axis of resistance,” a power bloc that includes Iran, Iraq, Syria, Hezbollah, and Hamas in Palestine.

With the successful implementation of the historic nuclear agreement between Iran and the P5+1, a new chapter has opened between Iran and the international community, including the United States. Nevertheless, the future path of bilateral relations between the United States and Iran is uncertain and many challenges exist as the two countries attempt to formulate new terms of engagement. What should U.S. policy be towards Iran after the nuclear agreement? Can the agree­ment open the door to effective collaboration on areas of mutual interest, especially given the rising security challenges and rapidly changing dynamics of the Middle East? Or, will strategic rivalries between Iran and the United States con­tinue to shape and impede cooperation?