Comprehensive Test Ban Treaty and Nonproliferation
The Comprehensive Test Ban Treaty will have both technical and political impacts on nuclear proliferation. Technically, the treaty will not have the value today that it would have had in the 1950s or 1960s when the great leaps in nuclear weapons development depended on nuclear tests. Information about nuclear weapons design is now widespread, as are the technologies for making such weapons. But, because the treaty will create a powerful international norm against testing, both the nuclear states and the threshold states (those with undeclared nuclear arsenals) will be less able to create weapons much different from those they now hold. And perhaps the greatest impact will be in reinforcing the Nuclear Non-Proliferation Treaty, so that the number of nuclear-weapon states is less likely to expand.
Technical Impacts
As Pakistan (before its nuclear tests in May 1998), South Africa, and Israel have demonstrated, relatively simple nuclear weapons can be made without nuclear tests. All these nations may, however, have benefited from nuclear design information provided by others. And South Africa designed weapons that would not need testing. Its gun-type (uranium) bomb design was similar to the US nuclear bomb dropped on Hiroshima in 1945, which was not tested before use. Only the implosion-type Nagasaki bomb was tested. Even back in 1945 nuclear tests were not required to make a nuclear bomb.
A comprehensive test ban would, however, make it harder for new nuclear nations to build the more sophisticated (smaller, lighter) nuclear weapons that ballistic missiles can more readily deliver. In particular, tritium boosting (which increases the explosive power of the primary stage of nuclear weapons that are based on nuclear fission) and thermonuclear weapons (which achieve much greater explosive power using nuclear fusion) depend heavily on nuclear testing. These improvements could allow threshold nations to expand their arsenals by making more weapons with the same stock of fissile material (plutonium or highly enriched uranium).
Nuclear Weapons States
Without testing, the five original and two newly declared nuclear weapon states will be less confident about any new types of nuclear weapons they develop. Thus a test ban will effectively limit future weapon-development activities. However, exactly where that limit falls for each nuclear state is an issue of some debate.
A comprehensive test ban would certainly preclude development of new generations of nuclear weapons, such as x-ray lasers and electromagnetic pulse weapons. But what about modifications to existing warhead designs? How much could the United States change tested designs and still retain confidence in them? How will the new warhead experimental facilities to be built under the US Stockpile Stewardship program affect this calculus? Other nuclear states are likely to be somewhat less able to conduct such simulation activities.
Political Impacts
A central value of the comprehensive test ban today is the political benefits of the agreement and the norm it establishes for international behavior. These benefits have already been felt in the extension of the Nuclear Non-Proliferation Treaty. Although that treaty was extended before negotiations for the Comprehensive Test Ban Treaty concluded, commitments in 1995 by the original five nuclear states to conclude a comprehensive test ban were essential to achieve the extension. The Nuclear Non-Proliferation Treaty is a central element in US nonproliferation efforts, and its continued viability is much more important to US security than are additional US nuclear tests.
Above all, the Comprehensive Test Ban Treaty establishes the international norm that nuclear testing is no longer an acceptable activity for any nation--even those that do not sign. The fact that the nuclear states have foresworn testing is vital. Although most nations have foresworn the bomb under the Nuclear Non-Proliferation Treaty, the existence of nuclear arsenals in the weapon states is a continuing sign of inequity in the international system. To correct this imbalance, the Nuclear Non-Proliferation Treaty needs to be buttressed with global, nondiscriminatory agreements like the comprehensive test ban.
