Prior to September 11 and the subsequent anthrax attacks, the threat of national and terrorist acquisition of chemical and biological weapons often were seen as separate problems, requiring separate solutions. Now, however, we must recognize, that these two proliferation problems are closely linked, in that assistance from national programs is likely to be critical to terrorist efforts to acquire and use chemical or biological weapons successfully. According to U.S. government officials, about a dozen countries are believed to have chemical weapons programs and at least thirteen are said to be pursuing biological weapons. These national chemical and biological weapons programs pose a direct threat to U.S. military forces and to our friends and allies in the two regions where most of this proliferation has occurred " Northeast Asia and the Middle East. They also pose an indirect threat, because of their potential to serve as a source of chemical and biological weapons expertise or materials to other national or terrorist programs. Elisa D. Harris is a Senior Research Scholar at the Center for International and Security Studies at Maryland.