Judging from press accounts, the most recent round of negotiations over Iran’s nuclear program wrestled with the question of whether the Islamic Republic has a right to enrich uranium under the Nonproliferation Treaty (NPT), to which Iran is party. It might seem surprising that this esoteric question would be a stumbling block to such high-stakes diplomacy. After all, any bargain that the United States and Iran struck would either permit the country to continue enriching uranium or not. Whether it has a right to do so seems semantic.

In truth, Iran’s right to enrich has been at the heart of the nuclear negotiations for the past decade, and it deserves its central place in talks today. Matters of legal theory aside, the right to enrichment has become a shorthand for the real central issue in the negotiations -- whether Iran will be allowed to maintain a nuclear weapons option as part of a nuclear program under international safeguards.

Whether the NPT guarantees signatories a right to enrichment is a long-standing dispute among the parties to the treaty. The NPT never uses that phrase, but Article IV of the text states that “nothing in this Treaty shall be interpreted as affecting the inalienable right of all the Parties to the Treaty to develop research, production and use of nuclear energy for peaceful purposes without discrimination and in conformity with Articles I and II of this Treaty.”

Iran and many other parties to the NPT (including China, Germany, and Russia) have interpreted the NPT as guaranteeing a member’s right to develop enrichment for “peaceful purposes” under International Atomic Energy Agency (IAEA) safeguards. The United States, France, and the United Kingdom argue that the treaty does not guarantee a right to enrichment, only a right to “peaceful uses of nuclear energy,” without specifying what that right might include. (For its part, Washington has long argued that enrichment must be treated as a “sensitive” nuclear technology, meaning that it involves the direct production of fissile material that could be used for either military or peaceful purposes, and therefore poses an inherent threat to nonproliferation efforts. As a result, the United States has generally tried to discourage the spread of enrichment technology to additional countries, even for peaceful purposes.) Of course, in the absence of a court with jurisdiction to arbitrate disputes over the meaning of the NPT, it’s impossible to resolve the legal question.

But in the case of the Iranian nuclear negotiations, the United States and its partners have been making an additional argument -- that Iran’s rights under the NPT (whatever those might be) have been superseded by numerous UN Security Council resolutions since 2005 that demand that Iran suspend enrichment and reprocessing activities until “confidence is restored in the purely peaceful nature of Iran’s nuclear program.” In this view, the UN Security Council -- by virtue of its mandate to maintain international peace and security -- has the authority and responsibility to demand that member states take actions to comply with the treaty and prevent proliferation. The resolutions are silent on how long such a suspension would last, how it would be terminated, and what kind of nuclear program Iran would be allowed post-suspension.

For its part, Iran rejects the legitimacy of the UN Security Council resolutions. It maintains that the IAEA was wrong to refer Iran’s nuclear issue to the Security Council in 2005 after its Board of Governors found that Iran had carried out nuclear activities “inconsistent” with its obligations under the NPT. (Under the IAEA charter, the Board of Governors is required to report “noncompliance” with IAEA safeguards to the UN Security Council for further action. The 2005 resolution on Iran uses the term “inconsistent” instead of “noncompliance,” which, Iran argues, makes the referral illegal.)

Of course, the legal distinctions would not matter as much if the world trusted Iran to maintain a substantial enrichment program without using it to produce nuclear weapons. Iran says its right to enrichment means that it must pursue enrichment on an industrial scale, sufficient to produce enough low enriched uranium to fuel a single light water nuclear power reactor, such as the Russian-built Bushehr nuclear power reactor. (Although Russia is contracted to provide fuel for the lifetime of the reactor, Iran argues it needs to have a backup fuel supply in the event that Russia fails to deliver.) Since nuclear power reactors require far more enriched uranium than nuclear weapons -- this is a matter of tons versus kilograms -- an industrial-scale enrichment plant would give Iran a plausible path to nuclear weapons.

In a breakout scenario, Iran could swiftly convert the facility from the production of low enriched uranium for reactor fuel to the production of highly enriched uranium for weapons. The time it would take for Iran to go nuclear -- measured by how long it would take to produce a single bomb’s worth of weapons-grade uranium in a given facility -- is subject to various technical qualifications and uncertainties, but clearly an industrial-scale enrichment facility with tens of thousands of centrifuge machines would create the potential for Iran to acquire a bomb before anyone could do anything about it. In a “sneak-out” scenario, which is more plausible, Iran could seek to build covert enrichment facilities in order to build nuclear weapons in secret, with less risk of detection and pre-emptive action before it was too late. An industrial-scale enrichment facility would help here, too. Iran could divert some of the resources earmarked for the large facility to a smaller covert plant. It could also use the excuse of the official facility to develop more advanced and powerful types of centrifuge machines. The IAEA has a number of ways to try to detect covert facilities, but in general, the larger overt facilities are, the more difficult it is to detect cheating.

For the United States and its partners, these scenarios are all too plausible. They believe that the primary purpose of Iran’s enrichment program is to create an option to produce nuclear weapons. Therefore, their primary objective is to limit the physical capacity of Iran’s enrichment program so that Iran cannot produce nuclear weapons and to ensure that, under the careful watch of international inspectors, any enrichment Iran conducts is entirely for peaceful purposes.

In this sense, it should not be a surprise that last week’s negotiations hit a wall. For years, the nuclear negotiations have stalled over precisely this point: legal terms that are a mask for the central issue in the negotiations. The P5 plus 1 (the United States, Russia, China, France, the United Kingdom, and Germany) believe that Iran is seeking a nuclear weapons option, and Iran refuses to accept its obligation to comply with UN Security Council resolutions.

In theory, it should be possible to come to a compromise on the issue of enrichment. The P5 plus 1 and Iran could agree on a final deal that would allow Iran to maintain a domestic enrichment program but impose physical limits on its scale and scope so that Iran could not quickly produce large amounts of weapons-grade uranium. A deal would also involve additional verification measures that would minimize the risk of breakout or sneak-out. Iran would be able to claim that its right to enrichment was respected but it has chosen to limit the exercise of its rights to provide assurances that its nuclear program is purely peaceful. To accept such an agreement, however, Tehran would need to make a strategic decision to abandon (at least for now) its efforts to acquire a nuclear weapons capability in exchange for comprehensive sanctions relief.

Optimists believe that the pressure of economic sanctions -- which brought about the election of President Hassan Rouhani and Iran’s willingness to negotiate in the first place -- may have already produced such a strategic shift. It’s more likely, however, that Iran is only offering tactical adjustments to slow or limit some elements of its nuclear program in hope of removing the sanctions without fundamentally sacrificing its long-term goal of acquiring nuclear weapons. By pursuing a phased approach to eliminating Iran’s nuclear weapons capabilities, the P5 plus 1 have indicated that they are prepared to accept an interim stage that slows Iran’s nuclear program in exchange for limited sanctions relief, while hoping to retain sufficient sanctions leverage (and the threat of future sanctions) to eventually compel Iran to accept stronger limits and intrusive monitoring.

Whether negotiators can agree on such an end state is questionable: there are no indications as of yet that Supreme Leader Ali Khameini is prepared to give up Iran’s nuclear weapons ambitions. Nonetheless, even an interim agreement is preferable to the continued expansion of Iran’s nuclear program toward a nuclear weapon. 

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  • Gary Samore, until recently President Obama's chief advisor on non-proliferation issues, is the Executive Director for Research at Harvard University's Belfer Center for Science and International Affairs.
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