Nuclear latency or a nuclear threshold state is the condition of a country possessing the technology to quickly build nuclear weapons, without having actually yet done so.[1] Because such latent capability is not proscribed by the Nuclear Non-Proliferation Treaty, this is sometimes called the "Japan Option" (as a work-around to the treaty), as Japan is considered a "paranuclear" state, being a clear case of a country with complete technical prowess to develop a nuclear weapon quickly,[2][3] or as it is sometimes called "being one screwdriver's turn" from the bomb, as Japan is considered to have the materials, expertise and technical capacity to make a nuclear bomb at will.[4][5][6][7][8][9] However, nuclear latency does not presume any particular intentions on the part of a state recognized as being nuclear-latent.[10]
Nuclear latency can be achieved with solely peaceful intentions, but in some cases nuclear latency is achieved in order to be able to create nuclear arms in the future, which is known as "nuclear hedging".[11] While states engaging in nuclear hedging do not directly violate the NPT, they do run the risk of potentially encouraging their neighboring states, particularly those they have had conflicts with, to do the same, spawning a “virtual” arms race to ensure the potential of future nuclear capability.[11] Such a situation could rapidly escalate into an actual arms race, drastically raising tensions in the region and increasing the risk of a potential nuclear exchange.[11]
In a paper written following the establishment of the JCPOA, a Counselor of the Nuclear Threat Initiative, John Carlson, outlined several criteria for use in helping to determine whether a state's nuclear program was run solely with peaceful intentions, or if the state was engaging in nuclear hedging:[11]
There are many countries capable of producing nuclear weapons, or at least enriching uranium or manufacturing plutonium. Among the most notable are Japan, Canada, Germany, the Netherlands, and Australia.[12] In addition, South Africa has successfully developed its own nuclear weapons, but dismantled them in 1989. Following the collapse of the Joint Comprehensive Plan of Action agreement some consider Iran a nuclear threshold state.[13] Taiwan and South Korea have both been identified as "insecure" nuclear threshold states—states with the technical capability to develop nuclear weapons (South Korea had been involved in nuclear energy technology since the end of the Korean War and possessed an active nuclear weapons program that was terminated in the mid-1970s with its signing of the Nuclear Non-Proliferation Treaty[14] while still engaging in some clandestine nuclear weapons research into the late 1980s[15]) and the security motivations to seriously contemplate such an option—since the publishing of a Mitre Corporation report in 1977.[16] US intelligence also believes Taiwan has designed devices suitable for nuclear testing.[17]
The number of states that are technically nuclear-latent has steadily increased as nuclear energy and its requisite technologies have become more available to a variety of states.[10]