The intelligence community's flawed assessment of Iraq's weapons systems -- and the Bush administration's decision to go to war in part based on those assessments -- illustrates the political and policy challenges of combating the proliferation of weapons of mass destruction. Examining a broad range of recent case studies -- among them Pakistan's development of nuclear weapons, North Korea's defiance of U.N. watchdogs, and Russia's transfer of nuclear and missile technology to Iran and China's to Pakistan -- defense policy specialists Jason D. Ellis and Geoffrey D. Kiefer find disturbing trends in both the collection and analysis of intelligence and in its use in the development and implementation of security policy.