Foreign Relations & International Law

Reinforcing the Nuclear Nonproliferation Regime

Doreen Horschig
Sunday, February 4, 2024, 9:05 AM
The increasing frequency of counterproliferation attacks demonstrates the importance of bolstering international nonproliferation efforts.
Iranian officials view a missile display during an exhibition by the Islamic Revolutionary Guard Corps Air Force in Tehran. Photo credit: M. Sadegh Nikgostar/FARS Media; CC BY 4.0 DEED.

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Editor’s Note: The Treaty on the Non-Proliferation of Nuclear Weapons and other nonproliferation regimes are meant to stop new states from acquiring nuclear weapons. My Center for Strategic and International Studies colleague Doreen Horschig finds that when these regimes are weak, some governments may turn to covert means to stop dangerous proliferation. Such measures, however, can backfire, and Horschig argues that it is vital to strengthen overt nonproliferation efforts.

Daniel Byman


The nuclear nonproliferation regime—the set of international agreements, institutions, and norms that have provided transparency about nuclear weapons capabilities, managed escalation risks, and deterred the development of nuclear weapons by non-nuclear states—is in crisis. Long-standing efforts that underpinned cooperation between nuclear powers have stalled or lapsed. The last standing arms control agreement between the United States and Russia, the New Strategic Arms Reduction Treaty (New START), is under threat. Russia and China are now trying to rewrite the rules of the nuclear order. Nuclear ambitions in South Korea, Iran, and Saudi Arabia are growing. The Saudi crown prince, Mohammed bin Salman, stated last year that his government is “concerned of any country getting a nuclear weapon,” and that if Iran did successfully develop a weapon, “we will have to get one.” And North Korea, which has defied the nonproliferation regime to develop its nuclear arsenal, continues to test an array of ballistic missiles.

There are several widely accepted reasons why the nonproliferation regime remains important. The primary benefit is that it deters countries from acquiring nuclear weapons, fostering global security and stability. Additionally, it promotes international cooperation, negotiation, and transparency. And the regime establishes a norm against nuclear weapons, discouraging their possession and use.

But there is another, less appreciated reason for maintaining and bolstering the nonproliferation regime: An effective regime makes riskier counterproliferation efforts less necessary. If diplomacy and negotiations fail and the system that has deterred nuclear weapons development unravels, states may take action against proliferators. There may be more covert incidents targeting military and nuclear facilities, which in turn could make the targeted states more eager and committed to acquire nuclear weapons in order to deter additional attacks. The emergence of nuclear proliferators can increase the risk of nuclear conflict, the potential for arms races, and the overall challenge of maintaining global stability.

The Counterproliferation Trend

Preventive counterproliferation attacks that target materials, commodities, personnel, or infrastructure related to a nuclear weapons program are becoming increasingly attractive to states that oppose the emergence of new nuclear powers. These operations are usually covert and employ nonconventional tactics, including air and drone strikes, assassinations, sabotage, and cyber weapons. Many of these attacks have unfolded quietly behind the scenes. These operations tend to be well cloaked, given that they are part of some of the most critical defense programs countries can have.

Despite the concealment, my research shows that there has been an increase in the use of covert counterproliferation operations. Seven of the 70 identified attacks targeting nuclear programs since 1942 have occurred after Russia’s invasion of Ukraine—more than in any other two-year period prior to 2022. Assassinations have been the most used tool to interfere with a country’s nuclear ambitions, followed by airstrikes, sabotage, cyber weapons, and—more recently—drone strikes. The frequency of these attacks is increasing.

All of these attacks have been intended to interfere with new and existing nuclear weapons programs. This includes, for example, the 2022 and 2023 drone attacks on Iran’s Parchin military complex and Isfahan Nuclear Technology Center, the 2022 cyberattacks on U.S. National Laboratories, and the alleged 2022 assassinations of Iranian scientists Ayoob Entezari and Kamran Aghamolaei. While Israel accounts for a considerable number of counterproliferation attacks to date, eight other states have also resorted to covert operations.

These operations carry several risks, though. First, since most of these operations violate either territorial integrity or sovereign rights, they can risk a retaliatory response from the target state or strengthen its determination to obtain nuclear weapons. Israel’s attack on Iraq’s Osirak reactor in 1981 triggered a nuclear weapons program where one did not exist previously. The attack significantly increased the risk of a nuclear Iraq. After it got started, Iraq’s nuclear program was hindered more by domestic factors and inefficient technologies, which delayed bringing the program to fruition.

Second, emerging technologies have been used increasingly in military strategies and counterproliferation campaigns. For example, on November 27, 2020, Israel used a satellite-controlled machine gun to kill Iran’s top nuclear scientist, Mohsen Fakhrizadeh. In a different incident, on May 14, 2021, North Korea breached the internal computer network of the South Korean Atomic Energy Research Institute, hacking several government officials. The intersection of counterproliferation and emerging technologies creates new challenges, such as potential errors in target interpretation, an increased likelihood of hasty decisions escalating tensions, and new difficulties in attributing attacks.

Third, counterproliferation can increase mutual suspicion among states, risking a cascading effect of intensified tensions and elevated potential for escalation. A characteristic of the functioning nonproliferation regime is transparency and trust, which would diminish if covert attacks increased. Instead, counterproliferation is leading to tit-for-tat escalation. For example, in response to Israeli interference with its nuclear aspirations, Iran escalated its targeting of Mossad cells in 2022. Then, in response to a 2023 Israeli drone attack on the city of Isfahan, which hosts four small nuclear research facilities, Iranian Ambassador Amir Saeid Iravani warned that Iran “reserves its legitimate and inherent right … to defend its national security and respond resolutely to any threats or wrongful actions by the Israeli regime, wherever and whenever deemed necessary.”

 Potential Proliferators

States that are most likely to pursue nuclear weapons require close monitoring. There have been signals from a handful of countries that they are toying with the idea of launching their own nuclear programs. The Saudi minister of foreign affairs, Prince Faisal bin Farhan Al-Saud, stated in December 2022 that “if Iran gets an operational nuclear weapon, all bets are off.” In early 2023, South Korean President Yoon Suk Yeol said outright that Seoul “will introduce tactical nuclear weapons or build them” if North Korea’s nuclear threat grows. The high public support for a South Korean nuclear weapon is well-known. Iran’s nuclear ambitions are apparent by more concrete steps, including through its acceleration of uranium enrichment to near weapons-grade levels in November 2023.

Aside from Iran, though, there is limited tangible evidence that these other countries are actively pursuing independent nuclear deterrents. In fact, in dialogue with Washington, they usually plead their peaceful intentions and claim they are not pursuing their own nuclear capabilities.

Strengthening the Nonproliferation Regime

Given the counterproliferation trend and signaled interest from a few actors, there is a need to prioritize strengthening the existing nonproliferation regime to discourage proliferators from developing nuclear weapons programs and dissuade their adversaries from considering military actions or other risky counterproliferation strategies. A comprehensive approach by nonproliferation stakeholders to mitigate the risk of nuclear proliferation and the need for counterproliferation should strengthen what works in the existing nonproliferation regime while also addressing reasonable critiques of the current system and warning of the perils of a system more reliant on counterproliferation measures.

First, stakeholders should reinforce the existing nonproliferation regime by continuing to be transparent about nuclear development, providing International Atomic Energy Agency (IAEA) access to nuclear sites, and reassuring states that are protected by nuclear umbrellas. Through these actions, the stakeholders can bolster the framework that discourages both qualitative and quantitative nuclear proliferation and promotes a shared commitment to disarmament. This includes addressing the nuclear ambitions of countries under the U.S. nuclear umbrella—including Japan and South Korea—by enhancing the credibility of U.S. commitments and signaling a continuous commitment to the security of allies. Other states not protected by U.S. extended deterrence should still receive support, but on the condition that they are transparent about their nuclear development. For instance, any further U.S.-Saudi nuclear cooperation should ensure Riyadh’s commitments to Section 123 of the U.S. Atomic Energy Act and ratification of the IAEA’s Additional Protocol that advance nonproliferation principles. Only if trust is continuously reinforced among allies can the perceived need for independent nuclear programs be mitigated.

Second, stakeholders should acknowledge and address tensions within the nonproliferation regime. To avoid triggering military options, it is crucial that states and nonproliferation institutions address the incongruities and interpretations of why the regime is weakened. The divisions between nuclear-weapon and non-nuclear-weapon states have intensified, but they share a preference for peaceful resolutions to nonproliferation crises over covert military strategies. All actors need to work together to reassess the reasons for this polarization and what progress toward disarmament—the stated goal of Article VI of the Treaty on the Non-Proliferation of Nuclear Weapons—is possible while accounting for geopolitical shifts and technological advances.

Finally, stakeholders must highlight the risks of covert operations in nonproliferation debates. Counterproliferation operations undermine the nonproliferation regime’s diplomatic approach, but the existing regime does little to check these actions and instead largely ignores them. The illegal nature of these attacks stands in stark contrast to the collective international interest in peacefully preventing the emergence of new nuclear weapons states. Shedding light on the risks inherent in covert operations is imperative for a more comprehensive and informed debate.

Strengthening the existing regime through bolstering its strengths and adopting selective reforms, while discouraging more aggressive strategies, would contribute to adaptable policy frameworks to address the complex issues surrounding nuclear proliferation and counterproliferation. The trend of increasing counterproliferation operations provides yet another reason why the nonproliferation regime is so important. Without it, the global nuclear order could change, with unpredictable consequences.

Doreen Horschig is an associate fellow with the Project on Nuclear Issues at the Center for the Strategic and International Studies and a nonresident research associate at the School of Politics, Security, and International Affairs at the University of Central Florida. Her research examines nuclear counterproliferation, nonproliferation, and norms contestation.

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