|Fig. 1: One of Canada's nuclear power plants, a symbol of that country's unused technological ability to construct nuclear weapons. (Source: Wikimedia Commons)|
The five great powers, those with permanent seats on the United Nations Security Council, are the only ones recognized by the United Nations as possessing nuclear weapons stockpiles. These countries are China, France, Russia, the United Kingdom, and the United States. All five are signatories to the UN Treaty on the Non-Proliferation of Nuclear Weapons (NPT), whose objective is to prevent the spread of nuclear weapons and the knowledge about those weapons, with the ultimate goal of complete disarmament by all countries.  All but five widely recognized countries - India, Israel, North Korea, Pakistan, and South Sudan - are party to the treaty, all of which excepting South Sudan are believed to have undeclared nuclear weapons stockpiles.
Outside of these two camps, there are several other nations that have the technical expertise and civilian nuclear reactors that would allow them to quickly construct nuclear weapons if they so desired. These countries are "latent" nuclear powers, since they could easily develop nuclear weapons if they wished to do so. Japan is the most talked-about such country, and has nuclear power since the 1960s. Openly building nuclear weapons is historically an untouchable subject for any Japanese leadership because of the legacy of the American atomic bombs dropped on Hiroshima and Nagasaki during World War II; in fact, Japan's entire military capacity is by American dictate meant for use only in defense. Various other American allies like Canada (see Fig. 1), Germany, South Korea, and Australia are considered to have weaponizing capability. A primary reason that they do not pursue nuclear weapons is the presence of the so-called American "nuclear umbrella."
Through its obligation to protect the other 27 members of the North Atlantic Treaty Organization (NATO), the United States promises to come to other states' defense with force that could include nuclear weapons. Separate agreements with Japan and Australia also guarantee those countries against outside hostility. The U.S. has routinely placed some of its nuclear weapons in European and Asian states as a deterrent to rivals like the superpower Soviet Union during the Cold War and other potentially hostile groups and countries. The presence of American weapons of mass destruction meant that countries with civilian nuclear programs did not feel the need to convert their capability into bombs. Russia, which inherited the Soviet Union's nuclear weapons, maintains a similar nuclear umbrella in its sphere of influence. Nuclear umbrellas thus appear to limit the proliferation of nuclear weapons by extending other countries' weapons to a non-nuclear power and removing that power's motivations to build bombs of their own. It is, however, important to consider the deterring potential of nuclear latency, and how its spread might nearly equate to nuclear proliferation.
There are 31 countries that developed the capacity to construct nuclear weapons between 1939 and 2012, but only 10 of these actually built nuclear bombs. The vast majority of the 21 states that do not possess nuclear arsenals developed nuclear capabilities for civilian usages, but are considered a "screwdriver's turn away" from weapons if they wish to develop bombs within a period of months -- they are latent nuclear powers. Latency presents serious questions about international security, because "policymakers run the risk of applying the 'right' policy in the 'wrong' situation, thereby exacerbating a latent arms race" that would lead to widespread weapons proliferation.  Latency can be a powerful tool for powers, because the mere knowledge that a state can have bombs in the future changes the balance of power.
Unfortunately, this is a dangerous implication for the nonproliferation movement. If nuclear latency is an effective deterrent, countries have a strong incentive to pursue latency in the form of civilian nuclear power plants -- plants that nuclear powers are often willing to sell to them under the ideals of Atoms for Peace. This United Nations doctrine advocates the spread of the benefits of nuclear power to as many people as possible, but appears to have inadvertently driven more states to within a screwdriver's turn of atomic weapons. The UN may be forced to reconsider its support for nuclear power, in favor of encouraging alternative energy resources that do not offer nuclear latency.
© Baker Tilney. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 "Treaty on the Non-Proliferation of Nuclear Weapons," United States Treaties and Other International Agreements, 21 UST 483, TIAS 6839 (U.S. Government Printing Office, 1950 - ).
 J. J. Wirtz, "Conclusions," in Security Assurances and Nuclear Nonproliferation, ed. by J. Knopf (Stanford Security Studies, 2012), p. 275.