Fifty years after the international community began efforts to prevent the spread of nuclear weapons to states beyond those recognized in the Nuclear Non-Proliferation Treaty (NPT), the era of nuclear proliferation may be over.

It may be argued that this is only a temporary respite and the next case of proliferation is surely just around the corner, but no new cases or even suspected cases of proliferation have arisen in over a decade. In fact, it is difficult to point to any state that might pursue nuclear ambitions any time soon. One reason for this is the dedicated, concerted effort to both deepen the global norm of non-proliferation and strengthen the regime designed to prevent the occurrence of nuclear proliferation. Another is that it is increasingly rare for modern states to possess both the political will and the technological capability to pursue nuclear weapons programs.

The most recent cases of proliferation took place in Iran, which was suspected of pursuing nuclear weapons in the late 1990s and early 2000s, and North Korea, which joined the “unofficial” nuclear club in 2005. The ongoing nuclear crisis on the Korean peninsula caused many to look at South Korea and Japan as potential falling nuclear dominos, but both have recently sought renewed assurance from the United States that its nuclear umbrellas remain both intact and reliable. Prior to this, Saudi Arabia was considered a most likely candidate to engage in proliferation, but that was based on predictions that Iran had the potential to acquire nuclear weapons.

Why Do States Proliferate?

Research on nuclear proliferation has identified three major causes or drivers of nuclear proliferation: political revisionism, isolationism, and the presence of nuclear threat.

States such as Brazil, India, and Syria that engaged in nuclear proliferation due to political revisionism to change the balance of power or capabilities in a particular region or within a given relationship, did so because they perceived it as a pathway to greater prestige and influence. That the NPT institutionalizes the exclusivity of the nuclear club only adds to the perceived utility of nuclear weapons as a mechanism of revisionism.

States that engage in nuclear proliferation because of isolationism perceive that nuclear weapons will be a pathway to legitimization, normalization and, more importantly, regime survival by forcing adversaries to engage with them. States such as Iran, Iraq, North Korea, Libya, and South Africa exemplify the types of states that have engaged in nuclear proliferation, at least in part, from a sense of being politically, diplomatically, or economically isolated.

Finally, virtually every case of proliferation can be explained in part by the presence of a nuclear-armed or proliferating adversary, dating from the creation of the Soviet Union’s nuclear weapons program in the late 1940s to the most recent cases of Iran (Israel) and North Korea (the United States and South Korea, by proxy). States motivated to engage in nuclear proliferation by the presence of such threats have historically done so because they believe that the only thing capable of deterring nuclear weapons are nuclear weapons themselves.

The Problem of Prediction

The unique ability of nuclear weapons to resolve the underlying causes of insecurity has led academics and practitioners to consistently predict an impending tidal wave of proliferation; President Kennedy predicted in 1963 that there would be 10 to 20 new nuclear states by 1975, when in actuality only two unofficial nuclear powers emerged (Israel and India). Similarly, a 2004-2005 survey of proliferation threats conducted by the office of then Senator Richard Lugar (R-IN), predicted that as many as seven new nuclear states would emerge by the year 2016, but there have been none.

Rather than the seven new nuclear states predicted by the experts polled in the Lugar survey, it is difficult to identify any state that, either now or in the foreseeable future, is likely to acquire or even pursue nuclear weapons. These experts might be forgiven for failing to anticipate the successful negotiation of the Joint Comprehensive Plan of Action with Iran, but even assuming that Iran had gone on to acquire nuclear weapons, it is difficult to identify other dominos that would have fallen in the time frame under consideration.

The reality, rather, is that there have been remarkably few cases of proliferation and their frequency has been in steady decline for the better part of three decades, standing in stark contrast to what both academics and policy-makers routinely predicted. The data clearly shows that there have been no reported cases of nuclear proliferation in over a decade, a trend that is likely to continue into the foreseeable future.

Why No More Cases of Proliferation?

The principal reasons that there are likely to be no more cases of nuclear proliferation are that all those states that have the correct combination of political will and at least some components of a nuclear weapons program have either successfully acquired nuclear weapons (the latest being North Korea); attempted to acquire nuclear weapons but ultimately decided to abandon their pursuit and are not likely to go down the path of proliferation again (South Korea during the 1970s); and/or become firmly embedded in the non-proliferation regime (Japan, South Korea, Saudi Arabia, and Iran). To pursue nuclear weapons today, a state would either have to engage in diversionary/clandestine proliferation or would have to withdraw from the NPT prior to their production of nuclear weapons, both of which would incur substantial political cost. And while North Korea both illustrated that withdrawal from the non-proliferation regime could be accomplished and provided a roadmap other states could follow, it is difficult to imagine another state arising with the same unique combination of attributes (diplomatic isolation, technological wherewithal, nuclear-armed adversaries, despotic regime, etc.), such that the benefits of engaging in nuclear proliferation might be perceived by a regime as outweighing its costs. Furthermore, the North Korean case illustrates that the perceived benefits that might have been gained from engaging in nuclear proliferation in the past, such as using the threat of nuclear weapons as a means of forcing diplomatic engagement, are no longer valid.

Further decreasing the likelihood of future cases of proliferation, the United States and the international community have become much more sensitive to the importation and exportation of nuclear weapons-related (often called dual-use) technologies; due to such events as the discovery of the A.Q. Khan network in 2004. This increased sensitivity led, at least in part, to the creation of the Proliferation Security Initiative (2003) and the passage of United Nations Security Council Resolution 1540 (2004), both of which have been remarkably successful at preventing the acquisition of nuclear technologies by both states and non-state actors.

States have not only become more sensitive to the spread of nuclear weapons-related technologies and more adept at preventing it, they have also become much more capable of discouraging others from engaging in nuclear proliferation. Iran, for example, had one of the most significant and advanced nuclear infrastructures and a strong motivation to acquire nuclear weapons, but ultimately ended its pursuit because the United States and others were able to both cut off existing avenues of acquisition and alter the decision-calculus within the leadership of the Islamic state by imposing economic sanctions, severing formal diplomatic ties and taking other steps that made nuclear weapons less desirable..

Does This Mean That Proliferation is Impossible?

That it is difficult to identify any state or states that either currently have or are likely to have the correct combination of political will and technological capability to pursue nuclear ambitions does not necessarily mean that future cases of proliferation are impossible. This is particularly the case if either of these two necessary conditions change. Rather, it suggests that as long as the present conditions are maintained and, perhaps even more advisably, strengthened, proliferation probably will not happen. It is thus important that United States and others not adopt policies, such as the withdrawal of the U.S. nuclear umbrella from the Korean peninsula, that might foster the pursuit of nuclear weapons and their related technologies by others.

Conclusion

While the end of the era of nuclear proliferation should be lauded, it should also give pause. Prioritizing proliferation prevention has been possible because the threat has either been constant or has reoccurred with relatively normal frequency. As the last case of proliferation fades further and further into history, it may become politically difficult to allocate resources to preventing proliferation, particularly as other pressing threats, such as bio- and cyber-terrorism, continue to emerge. The time to act to keep nuclear proliferation a thing of the past is now. This includes renewing the push for the universal ratification of both the International Atomic Energy Agency Model Additional Protocol agreements and the Comprehensive Test Ban Treaty.

The era of nuclear proliferation is most likely over – but action is needed to keep it that way.

Todd C. Robinson is a Stanton Nuclear Security Fellow at the nonprofit, nonpartisan RAND Corporation.

Image: National Nuclear Security Administration