Durable Institution Under Fire? The NPT Confronts Emerging Multipolarity

The regime built around the 1970 Treaty on the Non-Proliferation of Nuclear Weapons (NPT) has helped curtail the spread of nuclear arms for fifty years. In hindsight, it is remarkable only nine states possess the world’s most powerful weapon. The NPT achieved much success during Cold War bipolarity and U.S. unipolarity in its aftermath. But today, China’s rise and Russia’s resurgence have ushered in a new era of emerging multipolarity. Can the treaty withstand the potential challenges of this dynamic environment? There is a real risk that multipolarity may shake the scaffolding of the nonproliferation regime, presenting a significant test to the NPT’s durability. This article identifies four essential elements of the nonproliferation regime: widespread membership, adaptability, enforcement, and fairness. History suggests bipolarity and unipolarity in the international system largely sustained and promoted these NPT features. When international regimes lack such elements, it sharply curtails their long-term efficacy.

International leaders and commentators bemoaning the unraveling of the post-World War II order often overlook the nuclear nonproliferation regime. While this regime receives less attention than trade policy or the global state of democracy, for five decades it has been quite successful preventing states from building nuclear weapons (Budjeryn, 2016; Müller & Schmidt, 2010; Rublee, 2009; Sagan, 1996–1997). The 1970 Treaty on the Non-Proliferation of Nuclear Weapons (NPT) is the foundation of the nuclear nonproliferation regime, the set of institutions and activities aimed at curtailing the spread of nuclear weapons and fissile materials. During treaty negotiations in the 1960s, delegations anticipated many more states would develop nuclear weapons. Over 30 states have explored the nuclear option (Bleek, 2017, p. 8), but only four now have nuclear weapons beyond the five nuclear arms possessors codified by the NPT. Nine nuclear-armed states is a far cry from dozens that would exist if all capable states had pursued nuclear weapons. Moreover, this regime has adapted when weaknesses became apparent, and oftentimes, rules have been enforced and cheaters punished.

Yet, the NPT’s success may be a product of the times. The United States and Soviet Union cooperated during Cold War bipolarity to establish the treaty and promote nuclear nonproliferation (Coe & Vaynman, 2015; Herzog, 2021a; Shaker, 1980). The superpowers did so for strategic rationales, including maintaining their military advantages, retaining influence over allies, and avoiding entrapment in nuclear wars among weaker states (Colgan & Miller, 2019; Kroenig, 2009; Verdier, 2008). The regime expanded for similar reasons under unipolarity and U.S. leadership (Gibbons, forthcoming; Onderco, 2021). Several scholars have pointed to Washington’s prioritization of nonproliferation and its longstanding great power position to explain the NPT’s success (Gavin, 2015; Hunt, forthcoming; Levite, 2002–2003; Miller, 2018).

However, bipolarity and unipolarity no longer characterize the international system. Russia has rebounded from its 1990s domestic turmoil and showcased its military power in the Crimea, Georgia, and Syria. With around 48% of the world’s nuclear weapons (Kristensen & Korda, 2021) and cyber capabilities on display in Estonia in 2007 and during the 2016 and 2020 U.S. presidential elections, Moscow’s influence cannot be ignored. Far from a paper tiger, Russia appears to be a “persistent power” (Kofman & Kendall-Taylor, 2021). Likewise, China’s rapidly growing economy, naval operations in the South China Sea, development of hypersonic missiles, and the vast aspirations of its Belt and Road Initiative highlight Beijing’s role as a great power (Mearsheimer, 2021).

A new environment of “emerging multipolarity” has arrived to challenge the vestiges of the U.S.-led international order. Disputes over human rights norms like the Responsibility to Protect (R2P) and the rise of parallel development banking institutions like the Asian Infrastructure Investment Bank are illustrative (e.g., Pratt, 2021). How the nuclear nonproliferation regime will fare under multipolarity remains an open question. After all, the NPT has so far required significant leadership and cooperation from great powers for its creation and maintenance. The regime’s long-term viability hinges on Russian and Chinese willingness to uphold the status quo.

Successful international regimes are diverse in their institutions, activities, and composition. Some characteristics are common across such regimes; without them, crises of legitimacy and efficacy will likely materialize. This article identifies four salient elements that have been pivotal to the NPT’s success preventing the spread of nuclear weapons: widespread membership, adaptability, enforcement, and fairness. We demonstrate how and why these mechanisms have been integral to the regime. While the dynamics of bipolarity and unipolarity largely helped sustain and promote these features, we explain why the dynamics of multipolarity might do the opposite. Emerging multipolarity thus presents a significant test to the durability of the nuclear nonproliferation regime.

The article proceeds in six sections. First, we review existing research on factors that contribute to international regimes. Then, we offer four sections discussing each of the aforementioned mechanisms. These sections show how specific features underlay the success of the NPT during bipolarity and unipolarity, and they assess treaty prospects in a multipolar international order. Finally, we conclude with implications for nuclear policy.