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PolicyWatch 2989

Iran After the JCPOA Withdrawal (Part 1): Lessons from Past Pressure Campaigns

Michael Eisenstadt

Also available in العربية

July 16, 2018

Tehran has generally responded to pressure by issuing threats, ramping up its nuclear activities, accepting temporary limits, and, when the heat is turned up, launching cyber, military, and terrorist operations.

This PolicyWatch is the first in a two-part series on shaping Iran’s potential responses to increased U.S. pressure on its nuclear activities. Read Part 2, which examines Tehran’s most likely actions following U.S. withdrawal from the JCPOA.

Iran is now assessing its options in the wake of President Trump’s May 8 announcement that the United States would be withdrawing from the 2015 Joint Comprehensive Plan of Action (JCPOA) and pursuing a policy of “maximum economic and diplomatic pressure.” As the administration implements that decision, U.S. officials should examine how Iran has responded to past pressure campaigns targeting its nuclear program. What do these responses say about how Tehran might react to Washington’s next moves?  


While the Islamic Republic’s nuclear program dates to 1984, negotiations to limit its nuclear activities did not gain traction until after its covert uranium enrichment program was discovered in 2002. Following more than a decade of off-and-on negotiations, increasingly harsh sanctions, and military threats, Iran agreed to the JCPOA in 2015, accepting temporary limits on its nuclear activities in return for sanctions relief. Telling patterns can be discerned in the regime’s responses during this period:

  • After the 2003 U.S. invasion of Iraq, Tehran reportedly halted its “structured” weaponization program to avoid providing a pretext for invasion of Iran, yet continued low-signature weapons R&D and made steady progress in its enrichment program.
  • Although Iran froze enrichment from 2003 to 2005 in response to foreign pressure, it used that time to fix technical problems with its enrichment program and continue construction of a uranium conversion plant at Isfahan.
  • When facing new pressures, Iran often threatened to increase its enrichment capacity/level, cease cooperation with the International Atomic Energy Agency, or build nuclear-powered ships and submarines if sanctions were not lifted.
  • In acceding to the JCPOA in 2015, Iran accepted temporary caps on nuclear activities while being allowed to continue centrifuge R&D. And it secretly hid its nuclear weapons archives—perhaps to facilitate the program’s restart at a future date.

In short, Iran often responded to pressure by incrementally increasing its enrichment capability and threatening even more dramatic progress to convince its adversaries of the futility of their efforts. And on several occasions it reluctantly accepted temporary freezes on certain activities as long as they did not preclude continued progress elsewhere, force it to concede its “right to enrich,” or compel it to acknowledge the program’s military dimensions.

Moreover, as foreign pressure intensified and broadened, Iran generally responded in kind:

  • Following cyberattacks on its nuclear infrastructure and Ministry of Petroleum and sanctions on its central bank and oil industry, Iran threatened to close the Strait of Hormuz in 2011, then conducted cyberattacks of its own on U.S. banking and financial institutions in 2012.
  • After assassins targeted five Iranian nuclear scientists, Tehran ordered attacks on Israeli diplomats in at least four Asian countries in 2012.
  • In response to a surge of unmanned aerial vehicle flights on its borders and inside its airspace, Iran attempted to shoot down American UAVs over the Persian Gulf in 2012-2013.


Tehran’s efforts to deflect pressure on its nuclear program did not substantially affect its regional activities, since the regime has traditionally decoupled the nuclear issue from its policies toward Syria, Iraq, Afghanistan, and the Gulf (with one notable exception: the previously mentioned 2011 threat to close the Strait of Hormuz if its oil industry was sanctioned). Neither intensified nuclear sanctions nor the desire to conclude a nuclear deal had a discernible impact on Iran’s intervention in the Syria war, its apparent decision to eschew proxy attacks on U.S. personnel in Iraq after 2011, or its arming of the Taliban (for over a decade now) to assist their fight against U.S. forces in Afghanistan. Elsewhere, Iranian harassment of U.S. naval vessels in the Gulf did not abate during or after nuclear negotiations (twenty-two incidents in 2015, thirty-six in 2016).

Iran did exercise restraint on ballistic missile activity at the height of negotiations (November 2014 through July 2015), conducting only one medium-range missile launch during this period. It also eased up on its offensive cyber operations, perhaps to create a more conducive negotiating environment (though cyber spying activities continued throughout the talks).

After the JCPOA was finalized in July 2015, however, Iran urged Russia to intervene in Syria while temporarily surging its own forces there starting in September to repel a rebel offensive that threatened the regime. It also ramped up its medium-range ballistic missile launches (nine in the year after the JCPOA, four the following year), resumed aggressive cyber reconnaissance activities against U.S. and other targets, and accelerated its detention of U.S. residents (at least two in the second half of 2015 and five in the first half of 2016). It likewise stepped up support for Houthi rebels in Yemen around this time.


Iran continued many of these activities through the first few months of 2017, while pro-regime forces in Syria became more assertive—perhaps in part to test the new Trump administration. This prompted a series of U.S. military ripostes, including a cruise missile strike on Syria’s al-Shayrat Air Base following a regime chemical attack on civilians (April 2017); aerial interdictions of Iranian-supported militia units (three times in May-June 2017) and armed drones (twice in June 2017) that threatened rebels and embedded coalition advisors near the Syrian border town of al-Tanf; the shoot-down of a Syrian Su-22 fighter that attacked rebel units and U.S. advisors near al-Thawra (June 2017); the firing of warning shots across the bow of an Iranian naval patrol boat operating in a provocative manner (July 2017); and a strike on pro-regime forces that threatened Syrian Kurdish rebels and U.S. advisors near Deir al-Zour, reportedly killing 200-300 of them, including a large number of Russian mercenaries (February 2018).

Although these responses were limited in scope and mostly undertaken as force protection measures, they introduced an element of uncertainty into Iran’s calculus, and Tehran has generally taken a more cautious approach toward the United States since then. August 2016 was the last time Iranian forces detained a U.S. resident (they had previously arrested one or two every year or so for nearly a decade, and several still languish in prison). Likewise, they have not conducted any medium-range missile tests since July 2017, nor harassed U.S. warships in the Gulf since that August.

At about this time, however, Iran adopted a more assertive posture toward Saudi Arabia and Israel. It reportedly started work on missile production facilities in Lebanon, Syria, and Yemen; attempted a destructive cyberattack against Saudi Arabia’s oil infrastructure (August 2017); provided the Houthis with medium-range missiles used to attack Riyadh (beginning in November 2017); attempted a UAV attack against Israel from Syria (February 2018); and encouraged Hamas to attempt violent incursions across Gaza’s border with Israel (beginning March 2018). Iran and Hezbollah are also apparently helping Hamas establish a base of operations against Israel in southern Lebanon.

Some of these steps may be a logical extension of Tehran’s prior activities in these areas. Yet they might also reflect a desire to escalate attacks on America’s main regional allies just as Iran decided to deescalate (at least temporarily) in Syria and the Gulf.

Whatever the case, several conclusions can be drawn from this experience:

  • In response to actions against its nuclear program, Iran tends to issue threats, ramp up nuclear activities, accept temporary limits on the program when deemed necessary, and answer intensified pressure with cyber, military, and terrorist operations. Yet these attempts at nuclear pushback remain decoupled from its activities in Syria, Iraq, Afghanistan, and the Gulf—at least for now.
  • Despite pursuing an increasingly assertive policy, Iran remains sensitive to risks and costs and is tactically flexible. It will back off when met with a firm response in order to reengage at a more propitious time and place.
  • Since 2017, Iran has scaled down efforts to test U.S. forces in Syria and the Gulf, perhaps due to uncertainty about the Trump administration’s intentions. At the same time, it has stepped up activities against Israel and Saudi Arabia, perhaps to impose costs on Washington’s allies when it cannot punish the United States directly.


The balance of power inside Iran has also shaped the regime’s choices on these issues. In 2015, Supreme Leader Ali Khamenei may have attempted to balance acceptance of the JCPOA—which was a sop to pragmatic conservatives like President Hassan Rouhani—by giving Islamic Revolutionary Guard Corps commander Qasem Soleimani and other hardliners a freer hand to pursue their preferences in Syria and elsewhere. He may have done much the same thing in 2017, when he seemed to rein in the IRGC’s activities against U.S. forces in Syria while giving Soleimani a freer hand against Israel and Saudi Arabia.

Indeed, IRGC officials seem less risk-averse than the civilian leadership in Tehran, so if they gain a larger say in decisionmaking (e.g., as a result of Khamenei becoming incapacitated), Iran will likely act even more aggressively. The regime’s occasional propensity to overreach may also be exacerbated by a belief that momentum is on the side of Iran and its proxies, with their success in spurring Israel’s withdrawal from Lebanon (2000), contributing to America’s disengagement from Iraq (2011), and saving the Assad regime from a U.S.-Zionist-Saudi “conspiracy.” This may have given Tehran the confidence to send an attack drone into Israeli airspace in February, and to strike rebel forces and embedded U.S. advisors near Deir al-Zour that same month. Going forward, such a mindset could lead Tehran to respond to unprecedented nuclear pressure by intensifying its pushback in the nuclear and regional arenas (including Syria, Iraq, Afghanistan, and the Gulf), and by linking these activities in ways it has not in the past.

Michael Eisenstadt is the Kahn Fellow and director of the Military and Security Studies Program at The Washington Institute.