Michael Eisenstadt is the Kahn Fellow and director of The Washington Institute's Military and Security Studies Program.
Tehran will likely resort to measured countermoves in the nuclear domain at first, but successful U.S. pressure could spur it to challenge JCPOA limits, take action in non-nuclear domains, or push back against U.S. and allied forces.
In response to Washington’s withdrawal from the nuclear deal and reimposition of related sanctions, Iran will likely act in accordance with principles that have guided it through past nuclear crises. It may test or exceed nuclear limits imposed by the Joint Comprehensive Plan of Action (JCPOA), respond in kind to intensified pressure in other domains, seek alternative ways forward when confronted by a firm response, and attempt to mitigate the impact of sanctions by driving wedges between the United States and the international community.
Tehran may also ramp up its regional activities—which have not been part of its past nuclear pushback—thereby eroding the boundary between the two and raising the potential for escalation in one or both arenas. In the event that U.S. sanctions lead to drastic reductions in Iran’s oil income (an uncertain proposition at present) or Tehran concludes that Washington is actively pursuing regime change, it may resort to subversion or sabotage in the Persian Gulf, terrorist attacks, or even a nuclear breakout. The Trump administration’s actions in the coming months may help determine which path Iran chooses.
The Islamic Republic’s response will be shaped in part by the intensity of the U.S. pressure campaign, the manner in which Washington reacts to Iranian tests, and the degree to which Tehran believes America will back up its policy of maximum pressure with military force. If Iran can muddle through despite sanctions, it might continue observing JCPOA limits and decoupling its modest attempts at nuclear pushback from its non-nuclear and regional activities. If U.S. sanctions cut deeply, Iran might remain in the JCPOA to avert the snapback of international sanctions while pushing back in other arenas. In the worst case, Iran could push back on all fronts at once—though such a scenario seems unlikely for now. Thus, Tehran has a broad range of response options that it can calibrate according to circumstances.
Nuclear brinkmanship. Iran has indicated that U.S. withdrawal from the JCPOA might spur it to ramp up assembly of centrifuge components and resume production of uranium hexafluoride feedstock for enrichment—activities that do not violate the JCPOA but inspire fear that Tehran may eventually do so. The regime could also accelerate work on ballistic missiles whose range exceeds its current self-proclaimed limit of 2,000 kilometers. (It announced this limit in 2011 as a gesture to Europe but has since tested a longer-range system, the Khoramshahr, and threatened to exceed that range should Europe threaten Iran.)
If U.S. secondary sanctions are strictly enforced and impose a high cost, Tehran could eventually opt for riskier forms of nuclear brinkmanship. For instance, it could exceed JCPOA caps by enriching its uranium stocks beyond their current allowed level (i.e., 3.67 percent of U-235), or by stockpiling more than 300 kilograms of low-enriched uranium. It could also suspend implementation of the Additional Protocol or otherwise cease cooperation with the International Atomic Energy Agency. A slow, incremental breakout from JCPOA limits might complicate U.S. efforts to pressure Iran, especially if the regime declares that it will return to these limits once the United States rejoins the agreement (though key European states have indicated that any JCPOA violations would prompt the snapback of nuclear sanctions).
Should an incremental approach fail to yield sanctions relief, Iran might seek a threshold nuclear capability by quickly stockpiling large quantities of fissile material (the so-called Japan model) in order to ratchet up pressure on the United States. Or it could resurrect covert aspects of its nuclear program in order to create a small number of weapons, perhaps to restart negotiations from a position of strength and get sanctions lifted in return for agreeing to a freeze on its nascent nuclear arsenal (the so-called North Korea model). Either route, however, risks spurring military action by an apprehensive Israel or (less likely) by the United States. So far, President Trump has not indicated whether he would be willing to use force against Iran’s nuclear program; this might depend in part on whether diplomacy has contained the threat of war with North Korea.
Regional pushback. Since the early 1980s, Iran has declared that if it cannot export oil, then none of its neighbors will either. Thus, U.S. sanctions that severely curtail Iran’s oil income could prompt the regime to disrupt oil production and exports on the Arab side of the Gulf via cyberattacks, sabotage, or military action. Ultimately, such actions could target the Strait of Hormuz, the passageway for most of Iran’s exports and imports—though for that reason, Iran is unlikely to take steps that jeopardize its own ability to use the strait.
Moreover, if intensified U.S. pressure destabilizes the Islamic Republic, Tehran may decide to merge previously separate efforts to parry pressure on the nuclear program and undermine U.S. interests in Syria, Iraq, and Afghanistan. To this end, Iran might direct its proxies to resume or intensify attacks on U.S. personnel in those three countries.
Alternatively, Iran could punish the United States by intensifying activities against Israel and Saudi Arabia via direct action or proxies. And with the return of pro-Assad forces to southern Syria following the latest regime offensive there, Tehran might eventually try to destabilize Jordan in order to facilitate arms transfers to West Bank Palestinians—as Supreme Leader Ali Khamenei called for in 2014.
In response to the growing threat posed by Iran and its proxies during the Syria war, Israel has conducted well over 100 strikes inside Syrian territory since early 2013, hitting arms depots and weapons convoys destined for Hezbollah. And since late 2017, it has repeatedly struck Iranian military facilities there as well, in order to prevent Iran from transforming the country into a springboard for military action against Israel. If the situation is mishandled, these ongoing conflicts could become entangled with the nascent Iranian nuclear crisis, sparking a war that no one seems to want—at least for the moment.
Now that Washington has withdrawn from the JCPOA, how can it shape Iran’s reactions while most effectively promoting U.S. interests in the region? Concerted, unified action is essential, guided by the following principles:
A comprehensive strategy. The United States needs an Iran strategy that integrates all elements of national power, as sanctions alone may not suffice. To reduce the possibility of suboptimal decisions based on impulse or political expediency, the administration should adopt a structured approach that clearly links means to ends while highlighting the costs, benefits, and tradeoffs involved in each choice. This includes acknowledging the risks involved in the policy of maximum pressure, which might convince Tehran that it has nothing to lose by disrupting regional oil shipments or attempting a nuclear breakout.
Plan B. Even as it implements its pressure approach, Washington needs hedging measures to offset the risks inherent in this policy. This means readying options for containing a reconstituted Iranian nuclear program if the regime rejects negotiations and proves adept at curbing domestic unrest—especially if the Trump administration or Israel prove unwilling or unable to deal with the program militarily.
Pushing back in Syria—and beyond. Countering Tehran’s proxy and military operations in Syria (and elsewhere) is essential to undermining Iran’s ability to push back against nuclear sanctions with regional actions. To this end, the United States should weigh in with Russia on preserving Israel’s ability to disrupt Iranian efforts at transforming Syria into a platform for projecting power in the Levant.
Backstop sanctions with covert/military options. Washington should signal Tehran that if it ever rebuilds its nuclear program, the United States would launch a covert campaign to destabilize the regime and force it to divert additional resources to internal security—playing on Iranian fears of an externally inspired “soft revolution.” The goal should be deterrence, not regime change. And to deter an Iranian nuclear breakout, the United States should preserve its readiness to undertake a preventive strike on the nuclear program if necessary. Washington should also warn Tehran that if its forces or proxies target U.S. personnel, then Iranian personnel will be targeted in response—in much the same way that al-Qaeda and Islamic State leaders have been targeted.
Prepare to get as well as to give. Tehran’s modus operandi is to reciprocate hostile acts in order to bolster deterrence; thus, U.S. cyberattacks could beget Iranian cyberattacks, and measures to slash Iran’s oil income could beget oil disruptions across the Gulf. Washington should therefore avoid actions that may engender responses it is ill prepared to deal with—for instance, instead of a total oil cutoff, it could ensure that Iran has just enough oil income to stop short of disrupting Gulf Arab exports. Likewise, if Washington overreaches by actively promoting regime change, it could induce Tehran to overreach by intensifying proxy attacks on U.S. personnel in the region and launching terrorist attacks on American interests there. (Indeed, fears of regime change have apparently led Tehran to resume the assassination of Iranian opposition activists in Europe after a decades-long hiatus.)
Friends should not surprise friends. Washington should press its allies to coordinate their actions against Iran more closely, so that the United States is not inadvertently implicated in them and targeted in response. This may have occurred in October 2016, when a Saudi airstrike in Yemen that killed more than 140 funeral attendees seemed to spur several attacks on the destroyer USS Mason by Iranian-linked Houthi rebels. Similar reprisals could occur in response to an apparent Israeli strike this June that killed more than fifty Iranian-backed Iraqi fighters in eastern Syria.
Restore U.S. credibility for leverage and deterrence. The longstanding U.S. credibility gap with Tehran could complicate efforts to shape the regime’s future choices. The restrained American reaction to Iranian-sponsored attacks on U.S. personnel in Beirut (1983), Saudi Arabia (1996), and Iraq (after 2003) taught Tehran that it can wage proxy warfare against the United States without risking a military response. Given President Trump’s public opposition to a long-term U.S. military presence in Syria and the yawning gap between his words and actions on Iran, much needs to be done to repair U.S. credibility.
The right policy balance. The challenge for Washington is to impose sufficient costs to bring Tehran back to negotiations, but without prompting Iranian actions that the United States is ill-prepared to deal with or that could spark a regional conflict. Much will depend on whether Tehran acts with caution or is emboldened to overreach as a result of its recent successes in the region and the mixed messages it has received from Washington. Altering Tehran’s risk calculus and shaping its incentive structures—while acting with prudence—will be key to both escalation management and policy success.
Michael Eisenstadt is the Kahn Fellow and director of the Military and Security Studies Program at The Washington Institute.