On March 23, legislators from both the Republican and Democratic parties introduced bills in the U.S. House of Representatives and Senate to expand sanctions against Iran. Both bills would bolster enforcement of the arms restrictions under Security Council Resolution 2231 and target Iran’s ballistic missile program.

In addition, the Senate bill (the “Countering Iran’s Destabilizing Activities Act of 2017”) would address terrorism-related sanctions on Iran’s Islamic Revolutionary Guard Corps (IRGC). It would also freeze existing sanctions designations that would eventually need to be lifted to comply with the Joint Comprehensive Plan of Action (JCPOA), the nuclear deal agreed between Iran and the five permanent members of the United Nations Security Council plus Germany.

Although some sponsors emphasized that the Senate bill was not designed to impede the nuclear deal, former Obama administration officials and advocacy groups have expressed concern that it could obstruct the United States’ fulfillment of its sanctions relief commitments under the JCPOA, giving Iran a pretext to impose conditions on its own performance under the deal. A close reading suggests that the bills would complicate implementation of the deal, but if interpreted and implemented carefully, they would not necessarily derail it.


Resolution 2231, which endorsed the nuclear deal and terminated previous UN sanctions on Iran, imposed binding restrictions prohibiting the export from Iran of all arms and related materiel. It also prohibited the transfer to Iran of certain heavy weapons—battle tanks, armored combat vehicles, large caliber artillery systems, combat aircraft, attack helicopters, warships, and missiles or missile systems—and related materiel.

The House bill would impose sanctions on those engaged in significant violations of these UN restrictions, which remain in effect until October 2020 (unless terminated earlier by a finding of the International Atomic Energy Agency that all nuclear material in Iran remains in peaceful activities).

The Senate bill, by contrast, covers a narrower set of activities. It imposes sanctions only for transfers to or from Iran of the heavy weapons listed above and related materiel. It does not do so for exports of small arms and light weapons from Iran—even though such exports are prohibited under Resolution 2231.

Using U.S. designations to penalize violators of the UN arms restrictions (as the House bill does) is a sophisticated way of leveraging powerful unilateral tools to promote enforcement of multilateral measures that otherwise lack teeth. In that light, the Senate bill’s omission of sanctions for UN-prohibited small arms exports is curious—particularly as there have been multiple reports, including by the U.S. military, of interdictions of small arms assessed to have originated in Iran.


The Senate bill would impose sanctions on those who engage in activity that has materially contributed (or risks materially contributing) to Iran’s ballistic missile program or other weapons of mass destruction-capable delivery systems. This would extend to their affiliates and agents as well as those knowingly supporting them.

In many respects this replicates the State and Treasury Departments’ existing discretionary authority to make ballistic missile-related designations under Executive Order 13382. However, in some areas the Senate bill goes further—such as by requiring designation of those who control the persons contributing to Iran’s ballistic missile program. The House bill’s ballistic missile sanctions provisions are structured differently and focus more clearly on state actors but appear intended to cover much of the same activity. However, the House bill does not require sanctions on those who exercise due diligence to avoid proliferation in their activities.

As a general matter, caution is warranted when making discretionary sanctions mandatory. Discretionary authority is generally drafted and interpreted expansively, to give policymakers a wide range of targeting options—including the ability to ramp up pressure over time, to incentivize desired conduct, and to hold designations in reserve to respond to future contingencies. When discretion disappears, the results may not fit into a coherent strategy. Likewise, when such broad authority must be deployed to its full extent, the results may appear unfocused and arbitrary, making the sanctions look like a pretext for punishment. In addition, because mandatory sanctions are often interpreted relatively narrowly (for the same reason that discretionary sanctions are interpreted broadly: to give policymakers flexibility), using the same terms in both might, ironically, lead policymakers to narrow their interpretation of the discretionary authority.

In addition to these general risks, the nuclear deal could face a significant challenge if any person that has been de-listed under it is found to have provided support for Iran’s ballistic missile program after enactment of this legislation, and is thus subject to mandatory designation (assuming the U.S. president declines to waive the imposition of such a designation, as he would have authority to do under both bills). Iran would likely portray such a re-designation as violating the nuclear deal. In such a scenario it could be argued that the designation is consistent with the deal because it is not nuclear-related, and is rather based on recent support for Iran’s ballistic missile program. However, it remains to be seen whether Washington’s partners and sanctions enforcement allies would be convinced.


The Senate bill would require the imposition on the IRGC and its officials, agents, and affiliates of the sanctions applicable under Executive Order 13224—the global authority for discretionary terrorism-related sanctions designations. This section, which has no counterpart in the House bill, has attracted a great deal of attention. Some have argued it is high time to designate the IRGC as a terrorist organization, others have warned that doing so would endanger U.S. troops fighting the Islamic State, and some Congressional offices reportedly see it as a clever way of appearing to designate the IRGC as a terrorist group without actually doing so.

If this section stays in the bill despite the concerns expressed about it, the significance may be mostly in the eye of the beholder. The IRGC and its officials, agents, and affiliates are already subject, under other authorities—including the Iran Threat Reduction and Syria Human Rights Act of 2012—to sanctions that are effectively identical to those applicable under Executive Order 13224. As a result, this section appears to require no further executive action. The bill does not actually designate the IRGC as a terrorist organization, require that the IRGC be so designated, or require the Executive Branch to determine whether the IRGC is a terrorist organization (as other proposed legislation would). And while the bill’s findings refer to the IRGC’s “support for acts of international terrorism,” the bill stops short of declaring the IRGC to be a “terrorist organization.” This follows the Treasury Department’s approach, in 2007, of describing the IRGC’s Quds Force as supporting terrorism (rather than as being a terrorist group).


The Senate bill would also require the retention of existing sanctions designations imposed for contributing to Iran’s ballistic missile program. This has implications for the nuclear deal because, in the JCPOA, the United States committed to the de-listing of 42 such individuals and entities on “Transition Day” (which will occur in October 2023 at latest).

While this section would make fulfillment of the deal more difficult, it would not make it impossible. Under any scenario, when Transition Day arrives, the administration will need to decide whether to de-list the 42 remaining targets and thus fulfill the United States’ commitments. The Senate bill would allow suspension of such designations if accompanied by a certification that the target had not supported Iran’s ballistic missile programs or terrorism in the prior three months, or by a presidential waiver that the suspension is vital to the national security interests of the United States. If such certifications or waivers were exercised, the designations would still loom in the background. If a target were found to recommence its support for Iran’s ballistic missile programs or terrorism after certification, then the bill requires that the sanctions be reimposed, while the presidential waiver must be renewed every 180 days. But this particular challenge would be faced well down the road.

Finally, the context for the whole package depends on the duration of these sanctions provisions. As drafted, the new sanctions in the Senate bill would remain in force indefinitely, whereas those in the House bill would be scheduled to end in 2026 with the rest of the Iran Sanctions Act.

The opinions and characterizations in this article are those of the author, who is on leave from the State Department, and do not necessarily represent the position of the United States government or the State Department.