Vol. 42 Executive Editor
I. Introduction and Background
The American withdrawal from the Joint Comprehensive Plan of Action (JCPOA) in 2018 raised numerous questions of international law, and a potential reentry into the accord by the Biden administration will implicate various new international law obligations and responsibilities. Two of the most pertinent questions as to the current status of the JCPOA are whether the United States violated international law through its withdrawal from the agreement, and whether the United States has the formal right to insist on “snapback” measures reinstituting sanctions on Iran despite its termination of the agreement.
After the JCPOA was negotiated between the parties in July 2015, it was formally incorporated into international law by the United Nations Security Council through Security Council Resolution 2231. Under domestic law, the United States government has labelled the JCPOA not a treaty, but rather a non-binding “political commitment,” meaning that it is not enforceable under domestic law. However, whether or not the document gives rise to international law obligations is an entirely different matter. There are two possible avenues through which the United States may have violated international law through its termination of the JCPOA. One is by violating a binding treaty obligation, were the JCPOA considered a treaty under international law. The other is by contravening Security Council Resolution 2231.
II. A Treaty or Not a Treaty?
Commentators disagree over whether, under international law, the JCPOA is considered a treaty, and therefore subject to the Vienna Convention on the Law of Treaties (VCLT). The Iranian regime argues that they are not violating international law by reengaging their centrifuges, but rather that they are taking appropriate countermeasures to the United States’ violation of their treaty obligations. Iran alleges the reimposition of sanctions constituted a violation of the United States’ international law obligation under the JCPOA. As a result, the Iranian regime resumed enrichment of uranium in violation of the text of the agreement in 2019.
The VCLT, to which the United States is a signatory, but not a party, defines a treaty as “an international agreement concluded between States in written form and governed by international law . . . .” At issue is whether the JCPOA is “governed by international law,” whether the parties to the JCPOA intended to create binding obligations under international law for themselves. There are two conceptions of the JCPOA, one of which envisions the agreement as creating binding legal obligations on all the parties involved, the other of which envisions the accord as merely a non-binding exchange offered by the United States proposing to cease sanctions in exchange for cessation of Iran’s nuclear program.
Although whether or not the JCPOA should be considered a treaty under international law is important to such issues as whether the United States needs to compensate Iran for their violation of the accord, and who should act first to reengage with the JCPOA between the two countries, it is ultimately incident to whether the Iranian regime is entitled to work towards a nuclear program. The Vienna Convention on the Law of Treaties does not allow the unilateral termination of a multilateral treaty in response to its breach by one party. Although “specially affected” states may temporarily “suspend” their commitments in response to a material breach, Iran’s actions still run afoul of international law insofar as the regime’s enrichment of uranium violates custom and the nuclear non-proliferation framework established in 1968. The Non-Proliferation Treaty (NPT), signed by Iran in 1970, prohibits all states other than the United States, Russia, China, Britain, and France, from acquiring nuclear weapons. Iran is not entitled, under international law, to take steps that would move toward a violation of the NPT, in response to the United States’ withdrawal from the JCPOA, regardless of the agreement’s treaty status.
III. Interpretation of Security Council Resolution 2231
As is typically the case in substantive issues of international law, questions of enforcement accompany questions of interpretation as to the best reading of Security Resolution 2231. The proper interpretation of Resolution 2231 is inevitably intertwined with what is best for the parties involved and who will ensure that a particular interpretation of the resolution is enacted. One measured approach, supported by many diplomats and emissaries of the European parties to the JCPOA,  suggests that although the United States is not justified in reimposing sanctions, its behavior does not rise to such a level so as to justify Iran’s reengagement of their nuclear program. This interpretation is the most prudent reading for the long-term health of the JCPOA, both incentivizing Iran to wind down its nuclear program and the United States to reenter the accord, and is also supported by the text, context, object, and purpose of the resolution.
The “calls upon” language used in the Security Council resolution suggests a less binding obligation than a “must,” or “shall,” obligation which would entail an enforceable violation of international law by the United States and purportedly justify some Iranian countermeasures. This language in the text of the Resolution seems to signal a less binding obligation.  The idea that the United States has not violated any international legal obligation is also based on legal precedent from the International Court of Justice and prior interpretations of Security Council resolutions.
However, Security Resolution 2231 also allows for members of the JCPOA to “snapback” sanctions against Iran in case of “significant non-compliance.” However, most commentators agree that this right is reserved for participants in the JCPOA, of which the United States is no longer one following their express withdrawal from the agreement. Moreover, the United States’ reimposition of sanctions is likely to violate several international principles, independent of whether the JCPOA constitutes a binding treaty under international law. The American justification for reinstituting snap back sanctions likely violates international law obligations to act in “good faith,” failing to institute the dispute resolution processes clearly outlined in the JCPOA. Even if the JCPOA is not a binding treaty establishing enforceable provisions of international law, the United States’ abrupt repudiation of their previous provision did not appear to be a “good faith” act. Additionally, the United States could be estopped from invoking the terms of the JCPOA after declaring it invalid. The estoppel doctrine suggests that the other parties’ reliance on United States participation in the agreement, which was withdrawn formally in 2018, voids any cause of action the country could claim under the deal.
Some institutionalists may be concerned about permitting an agreement such as the JCPOA to be deemed anything other than a treaty, and some American commentators may disagree with the country’s inability to institute snapback sanctions under the JCPOA. However, this intermediate position comports best with traditional interpretive principles of international law and also presents the most likely, and indeed perhaps the only, chance for the continued sustainability of the JCPOA.
 Steven Nelson, Iran Deal May Bind Next President, U.S. News & World Rep., July 3, 2015.
 John B. Bellinger III & Zachary Laub, How Binding Is the Iran Deal?, Council on Foreign Rels., July 23, 2015.
 Vienna Convention on the Law of Treaties, art. 2(1), Jan. 27, 1980, 1155 U.N.T.S. 331.
 Shokrani Maziyar & Muhammad Nasiruddeen, Joint Comprehensive Plan of Action (JCPOA): Interrogating the Legal Status of JCPOA and Contextualizing the Legal Implication of United States’ Withdrawal, 7 Global J. Pols & L. Rsch 56 (2019).
 Michael J. Glennon, The Iran Nuclear Deal: The Dispensability of Obligation, Just Security, Mar. 16, 2015; Iran’s Nuclear Program and International Law, Daniel H. Joyner 228.
 Elle Geranmayeh, Course Correction in US-Iran Relations: A Road Map for the Biden Administration, Eur. Council on Foreign Rels., Nov. 9, 2020.
 Parisa Hafezi, Iran says U.S., not Tehran, Should Act First to Resolve Nuclear Deal Row, Reuters, Jan. 28, 2021.
 Vienna Convention on the Law of Treaties, art. 60, Jan. 27, 1980, 1155 U.N.T.S. 331
 Mirko Sossai, ‘The Dynamic of Action and Reaction’ and the Implementation of the Iran Nuclear Deal, 66 Questions Int’l L.J. 5, 21 (2020).
 The Iran Primer, Iran and the NPT, United States Inst. Peace.
 Iran: The U.S. Brings Maximum Pressure to the UN, Int’l Crisis Grp. Rep., Aug. 19, 2020, https://www.crisisgroup.org/middle-east-north-africa/gulf-and-arabian-peninsula/iran/218-iran-us-brings-maximum-pressure-un.
 See Sossai, supra note 9, at 7.
 S.C. Res. 2231, ⁋ 11
 Matthew Lee & Edith M. Lederer, Showdown Set as US to Declare UN Sanctions on Iran are back, A.P. News, Sept. 17, 2020.
 David J. Scheffer, The Flawed U.S. Effort to Revive Iran Sanctions, Council on Foreign Rels., Sept 22, 2020
The views expressed in this post represent the views of the post’s author only.