THE WASHINGTON INSTITUTE FOR NEAR EAST POLICY APRIL 2021 POLICY NOTES NO. 103 Deterring Iran in the Gray Zone: Insights from Four Decades of Conflict Michael Eisenstadt resident Joe Biden has stated that if Iran returns to full compliance with the 2015 nuclear accord, known as the Joint Comprehensive Plan of Action (JCPOA), the United States will too, as a starting point for P 1 follow-on talks about Iran’s missile program and regional activities. The path to a stronger, longer, and broader JCPOA, however, may be tortuous and prolonged; success is not foreordained. Indeed, since the Biden administration took office, Tehran has already resumed proxy attacks on U.S. intrests in Image: The Japanese-owned Iraq, and has accelerated work on its nuclear program while limiting access tanker Kokuka Courageous, by international inspectors, in order to (1) build leverage, (2) roll back U.S. showing damage from an sanctions, and (3) obtain other concessions. Washington needs to be able to Iranian limpet mine attack in the Gulf of Oman, June 2019. deter or counter such moves and deny Tehran advantage in ways that do not Screenshot: U.S. Central hinder renewed diplomacy. Moreover, even if talks succeed, U.S.-Iran ties will Command. MICHAEL EISENSTADT DETERRING IRAN IN THE GRAY ZONE likely remain tense for years to come. Deterrence engendered by more effectively deterring and will therefore remain a core component of U.S. policy countering Tehran’s regional activities may enhance toward Iran as a way to manage tensions, avoid Washington’s ability to deter a potential future escalation, and deny Tehran leverage, thus creating nuclear breakout by Iran. an environment conducive to successful diplomacy. Gray zone deterrence poses particular challenges— because the entire gray zone modus operandi is designed to circumvent or defeat U.S. deterrence Insights from Past efforts. To successfully deter and counter Iran’s destabilizing regional activities and its gray zone Confrontations strategy, then, the United States will need to draw the right lessons from efforts going back over four A core belief of the Islamic Republic’s leadership decades. Fittingly enough, the most effective way is that the United States—the “Great Satan”—is the for the United States to counter these activities may foremost enemy of Iran, of Islam, and indeed of all be by adopting a gray zone deterrence strategy of oppressed peoples, and that they have a revolutionary its own.2 Doing so would rectify a major shortcoming obligation to overthrow the international order it of the JCPOA—its failure to address Iran’s desta- upholds.3 This ideological conviction found practical bilizing regional activities—while the credibility expression in the conduct of the regime once it seized power. As a result, the Islamic Republic was born into conflict with the United States and its leaders believe they have been at war with America—in one way or Author’s Note another—ever since. This paper builds on the analysis provided in the Thus, the seizure of the U.S. embassy and fifty-two author’s Policy Focus Operating in the Gray Zone: American diplomats and citizens as hostages in Countering Iran’s Asymmetric Way of War, published by Tehran in November 1979, and the 444-day crisis The Washington Institute in January 2020. However, that followed, set the stage for more than four this paper focuses more narrowly on the special decades of persistent enmity and intermittent challenges posed by Iran’s attempts to circumvent or conflict between the two countries.4 Examples have defeat U.S. deterrence efforts, and it incorporates included acts of unilateral and proxy terrorism such up-to-date insights from Iran’s campaign to counter the Trump administration’s policy of “maximum as the 1983 Marine barracks bombing in Beirut, the pressure.” In the coming years, deterrence will remain 1996 Khobar Towers bombing in Saudi Arabia, and the overriding policy imperative vis-à-vis Iran—and the 2011 plot to assassinate the Saudi ambassador to other gray zone actors such as China and Russia. This the United States in Washington DC. Other examples Policy Note, then, aims to help policymakers and have included several irregular warfare campaigns, planners meet the specific challenges of deterring among them (1) Iran’s efforts to counter U.S. convoy Iran’s destabilizing regional activities and countering operations (Operation Earnest Will) during the its gray zone strategy—as well as that of other gray Iran-Iraq War, (2) Iran’s support for Shia militant zone actors. groups “resisting” the post-2003 U.S. occupation of The author would like to thank Henry Mihm for his Iraq, and (3) the U.S.-Iran pressure/counterpressure invaluable research assistance, and Patrick Clawson, campaigns that both preceded the 2015 JCPOA and Michael Knights, Matthew Levitt, Vice Adm. John Miller followed the U.S. withdrawal from the nuclear deal (USN-Ret.), Farzin Nadimi, and Assaf Orion for their in 2018.5 (Iran’s efforts to counter the Trump comments on earlier drafts of this paper. administration’s maximum pressure policy are described in detail in appendix A.) 2 THE WASHINGTON INSTITUTE FOR NEAR EAST POLICY MICHAEL EISENSTADT DETERRING IRAN IN THE GRAY ZONE Deterrence and Iran’s Gray Zone on a dog-eared playbook dating back to the 1980s— using policy tools and a repertoire of actions that it Strategy has augmented over time. This repertoire includes both lethal and nonlethal activities in nearly all The Islamic Republic’s leadership has always under- domains—from hostage taking, embassy invasions, stood that its anti-American, anti–status quo agenda terrorist attacks, and harassment of and unacknowl- would bring it into conflict with the United States. edged attacks on maritime traffic, to weapons tests Accordingly, it developed an approach tailored to (for propaganda purposes); proxy and unilateral this challenge. Indeed, Iran’s gray zone strategy is drone, rocket, and missile strikes; information designed to circumvent or defeat U.S. deterrence operations; and all kinds of cyber activities. Iran efforts, with the aim of gaining advantage, obtaining leverages various asymmetries (e.g., conceptual, leverage, and increasing freedom of action—while operational, motivational, geographic, and temporal) managing risk, in order to prevent escalation and to gain advantage and achieve disproportionate avoid war. This modus operandi, which Iran has effects, and operates in a hybrid fashion—blending refined through its past interactions with the both conventional and irregular forces and modes United States, has been characterized by remarkable of operation—to achieve synergies.12 Continuities in consistency. It is based on three core principles: Iran’s approach have resulted in certain recurrent (1) incrementalism, (2) preserving a degree of patterns in U.S.-Iran deterrence and escalation deniability through proxy or covert/unacknowledged dynamics that must be understood if the United activities, and (3) avoiding decisive engagement of States is to more effectively counter Iran’s gray the enemy.6 zone strategy. If risk management is the main consideration The deterrence lessons of past Iran-U.S. confronta- guiding Iran’s gray zone strategy, deterrence is its tions, then, can be summarized as follows: foundation. Deterrence constrains adversaries, and thereby expands Iran’s options and affords it greater IRAN IS A LEARNING, ADAPTIVE ADVERSARY. freedom of action. To establish deterrence, Iran has, Iran tests and probes to determine an adversary’s over the past four decades, built a deterrence/ resolve and response thresholds, adjusting its warfighting triad consisting of (1) guerrilla and strategy according to its assessment of what is likely conventional naval forces capable of disrupting oil to work at a given time and place. An increasingly exports from the Persian Gulf;7 (2) an arsenal of diversified policy toolkit enables Iran to conduct missiles and drones capable of conducting long- nonlethal and lethal activities along several lines range precision strikes;8 and (3) a stable of foreign of operation, in diverse geographic arenas, and in proxies9—its Shia foreign legion—capable of projecting several domains, though it generally focuses on one influence throughout the region and acting as main line of effort at a time—perhaps to avoid task insurgents, counterinsurgents, and terrorists.10 overload or policy overreach. Tehran’s timing, choice Iran may now be adding a fourth leg to this triad— of targets, and methods emphasize reciprocity and offensive cyber operations.11 Deterrence, therefore, proportionality, and occasionally demonstrate a facilitates Iran’s gray zone activities, and gray zone degree of artistry as well as a flair for the dramatic. activities that demonstrate Iran’s precision-strike, sea denial, and terrorist capabilities bolster its Thus, in its recent efforts to counter the Trump deterrent posture. In this way, Iran’s deterrent and administration’s maximum pressure policy, Iran gray zone activities work hand in hand to reinforce graduated from simple to complex, and from each other. nonlethal to lethal, attacks. In May 2019, Tehran conducted a simple limpet mine attack against In implementing its gray zone strategy, Iran relies four oil tankers parked in an anchorage off the POLICY NOTE 103 3 MICHAEL EISENSTADT DETERRING IRAN IN THE GRAY ZONE coast of the United Arab Emirates; the next month, to counter the U.S. maximum pressure policy by it conducted a more complex limpet mine attack various Iraqi Shia groups, including