The Foreign Service Journal, December 2009

D E C E M B E R 2 0 0 9 / F O R E I G N S E R V I C E J O U R N A L 33 clear weapons and nuclear explo- sive testing in the 1990s (Russia and the U.K. in 1991, the U.S. and France in 1992, and the PRC in 1996). Three other states — India, Pakistan and North Korea — have conducted tests since 1996. The entry into force of the Compre- hensive Nuclear Test Ban Treaty would effectively make the nuclear weapon states’ voluntary commit- ments legally binding; prohibit any further nuclear explosive testing by India, Pakistan and North Korea; and ban nuclear explosive testing by any other states. It would thereby constrain both “ver- tical” proliferation (expansion of the nuclear weapons ca- pabilities of the nuclear weapon states) and “horizontal” proliferation (development of nuclear weapons capabili- ties by other states). While the CTBT prohibits nu- clear explosions, it would not pre- vent non-nuclear explosions or computer simulations to ensure the continued safety and reliability of existing nuclear weapons. There- fore, it should not preclude the U.S. from meeting Pres. Obama’s Prague commitment to “maintain a safe, secure and effective nuclear arsenal to deter any adversary, and guarantee that defense to our al- lies” for as long as the United States requires nuclear weapons to deter aggression. The CTBT is the fourth and most comprehensive treaty to constrain the ability of states to develop nuclear weapons by limiting their ability to test nuclear weapons or explosive devices. The multilateral Limited Test Ban Treaty, which entered into force in 1963, was the first nu- F O C U S The five states that the Nuclear Non-Proliferation Treaty acknowledges as having nuclear weapons have not conducted nuclear weapons or nuclear explosive tests for more than a decade. Buy all your travel guides, language books and pleasure reading through the AFSA bookstore. Buy the Amazon Kindle and download and read first chapters for free before you decide to purchase that new book. When you access Amazon.com through our bookstore all your purchases will benefit AFSA at no additional cost to you. Find State Department and AFSA Reading Lists Online at www.afsa.org/ads/books/ Start your purchase on our site: www.afsa.org/ads/books/