According to Senator Jon Kyl (R-AZ), the threat of missile proliferation has grown rapidly since the 1990s. A total of 120 nations now have ballistic missile technology, he said, and nations like North Korea and Iran are not only developing the technology, but selling it on the open market. Missile defense systems are growing as well; 27 nations now have some form of missile defense.
The most recent annual report from the Pentagon highlighted the growing threat of accidental or intentional launch of ballistic missiles, as well as the vulnerability of U.S. satellites to attack, as evidenced by China's 2007 missile test, which destroyed a satellite in orbit.
A defense official commenting on the proposal told the Washington Times that space-based ABM systems are necessary for global, rapid defense, "It's really the only way to defend the U.S. and its allies from anywhere on the planet". The official said such defenses were last considered during the late 1980s, as part of the Global Protection Against Limited Strike, or GPALS, a multi-prong system which used ground and sea-based interceptors, along with space-based platforms. The plan was cancelled by the Clinton Administration, which focused all work on short-range missiles only.
The U.S. announced last year that its ground-based Star Wars' missile defense system was operational and ready for use, though capable at present of covering only parts of the U.S. Plans to expand the system in Europe are under way.
Despite claims to the contrary, China is also apparently working on similar proposals, says China military affairs specialist Richard Fisher. The program, which China says it halted in the 1960s, has apparently been restarted with such systems as the SC-19 anti-satellite missile. According to Fisher, China is also trying to deploy space-warfare weapons, aircraft carrier groups, and a much larger MIRV'ed version of its nuclear ballistic missile arsenal.
Fisher, author of the new book, "China's Military Modernization: Building for Regional and Global Reach", says that by 2020, China "will be well on their way to assembling all the elements of global power that [the U.S.] has today".