I. Executive Summary

On January 2, 2020, the United States assassinated the commander of the Islamic Revolutionary Guard Corps’ Qods Force, General Qassem Soleimani, in Iraq and accused him of playing a role in an alleged attack on American troops by Iran-backed Shia militias. The assassination signaled a major escalation in the conflict between Iran and the United States. For a moment, the conflict ceased to be a proxy war characterized by efforts to keep tensions deniable and indirect and instead became a direct exchange of violence, with Iran responding to the assassination with a direct missile strike on U.S. forces.

The fallout of the assassination reflects the contradictions and uncertainty at the heart of Iranian proxy warfare strategy and its approach known as “forward defense,”¹ in which Iran seeks to use proxies in other countries to prevent conflict from coming within Iran’s borders. Iran’s strategy was developed over decades through its confrontations with the United States and regional rivals and historically has emphasized its willingness to eschew revisionist religious and ideological aims in order to pursue national interests.

The 2011 Arab Spring, with its threat to Iran’s key partner in Syria while opening opportunities in other areas, inaugurated a more uncertain era for Iran’s proxy strategy. This uncertainty has been heightened by an increasingly aggressive U.S. stance towards Iran. As a result, Iran has played up appeals to religious and ideological aims alongside more traditional forms of proxy mobilization in its forward defense strategy.

Though Iran continues to view and portray itself as pursuing defensive ends vis-à-vis the United States and other rivals, the means it uses tend to signal more revisionist aims, an issue Iranian policymakers recognize as a challenge but embraced anyways. In turn, this has encouraged the United States, and some of its partners, to pursue their own more direct policies of maximum pressure with regard to Iran.

It is far from clear whether Iran can sustainably pursue this strategy. Iran has a history of agile use of proxies and relatively successful navigation between the mobilization of religious and ideological appeals and the pursuit of national interest. However, Iranian society is showing signs of concern regarding the limits of forward defense. Iran’s rivals appear to have assessed that those strains are sufficient and that Iran will fold when confronted.

What is clear, however, is that this uncertainty brings with it the risk of repeated crises with the potential for escalation. Understanding whether and how stability in the relationship can be reasserted will require detailed examinations of the specific balances of national interest, ideological appeals, and Iranian control in the varied national contexts where the conflict is now playing out.

Key Findings:

• The 2011 Arab Spring and 2014 war against ISIS (Islamic State of Iraq and Syria) inaugurated a period of greater Iranian aggressiveness in its use of proxy warfare as it confronted a number of crises that increased Iranian threat perceptions.
• Iranian proxy warfare strategy is shaped by a desire to minimize costs to Iran and its people. As a result, it historically sought to maintain plausible deniability. Iran limited its direct contribution to the defense of the Assad regime in Syria, and has staffed its involvement in proxy wars generally from Islamic Revolutionary Guard Corps (IRGC) volunteers and by mobilizing local or foreign proxies, not by mobilizing the nation’s more general armed forces. Iranian strategists tout the limitations on direct intervention as a success of the strategy.
• While Iran has embraced more aggressive means in the form of a Forward Defense doctrine that seeks to give Iran strategic depth, it still views its objectives as largely defensive. Iran views itself as facing an American threat to its homeland—escalated by the Trump administration’s maximum pressure campaign—as well as an American threat to a key partner in Assad’s Syria, and an ISIS threat to Iranian partners and interests in Iraq.
• However, using proxy forces to wage war on the cheap and as a public deterrent has led Iran to rely upon ideological and religious appeals in order to mobilize fighters and signal its capabilities. In recent years, Iran has grown increasingly bold in making public statements that link together the movements it supports and its influence over their activities.
• Iran’s strategy contains a tension between its proclaimed defensive ends and its offensive means that have signaled a more revisionist intent to Iranian rivals. This tension holds the potential to escalate conflicts and thus make Iran’s strategy unsustainable given its desire to minimize costs. Iranian strategists are aware of the tension but supporters of the forward defense strategy view it as a manageable tension given its history of proxy warfare.
• Iran’s proxy strategy faces real political limits to its sustainability rooted in both domestic anger at the use of funds abroad, economic constraints, and backlash against perceived Iranian domination in countries where Iran seeks to build partners.
• The United States, for its part, has embraced a strategy of maximum pressure that views Iran’s strategy as unsustainable and prone to failure when conflict takes on a more direct character. Through sanctions and direct assassinations of key IRGC personnel, the United States hopes to force Iran to back down.
• It is not clear if Iran’s strategy is actually built to last, but the current moment is likely to be characterized by repeated crises with the potential to escalate into more direct confrontations because Iranian strategists view forward defense as an effective approach agile enough to manage tensions and the United States views it as an unsustainable policy that will fall apart when confronted.
• Policymakers should be aware of the ways in which Iran’s methods of ensuring cost-effective mobilization when pressed shape threat perceptions across the region, the IRGC’s own structure, and Iranian domestic politics. The effects of particular policies are likely to be complex and often unpredictable given the way transnational mobilization and signals interlink conflicts.
• An effective approach to this moment of crisis instability will require analysis of the sustainability of specific Iranian interventions. In some cases, like Iran’s support for Hezbollah, ideological and material ties make it unlikely that pressure can disrupt an established proxy relationship. In others, like Yemen, Iran’s commitment to the Houthis is more vulnerable to pressure. Other cases, like the Shi’a militias in Iraq, are less clear.