Soviet Union in 1991 engendered widespread concern that Russian nuclear weapons and material could end up in the hands of proliferants or terrorists. The ensuing decline in border security and the diminution of the role and power of the formerly ubiquitous security services signiacantly reduced the ability of Russia to safeguard these weapons and material. Another threat, the focus of this article, took a human form: Russian scientists with knowledge about nuclear, chemical, and biological weapons suddenly had greater leeway to visit or emigrate to any country of their choice, including so-called rogue nations seeking to produce weapons of mass destruction (WMD).1 And because of the greater ease with which Russian scientists could interact with the outside world, they could even sell their knowledge while remaining at home. Russia inherited the largest WMD complex in the world, with little government support for sustaining it at anywhere near Cold War levels. As a result, Russian science fell into a protracted crisis: salaries plummeted, funding for research dropped sharply, and the number of students pursuing careers in science dwindled. These developments gave Russian scientists both greater incentives and greater opportunities to sell their knowledge to governments or terrorist organizations that harbor hostile intentions toward the United States and other Western democracies. In response, the United States and other Western governments created a Russian Scientists and Rogue States