When Saddam Hussein's army invaded Kuwait on August 2, 1990, the United States took the lead in organizing stringent economic sanctions against Iraq. Since unilateral sanctions rarely succeed, coercive co-operation was a necessity. This innovative study shows that multilateral, or co-operative, sanctions are coercive not only in their pressure on their target but also in their origin: the sanctions themselves frequently result from coercive policies, with one interested state attempting to convince other through persuasion, threats and promises. To analyze this process, Lisa Martin uses a methodology combining game-theoretic models, statistical analysis, and case studies. She tests her hypotheses against 99 cases of economic sanctions since 1945 and then against 4 detailed case studies - the U.S.-led pipeline embargo, high-technology sanctions against the Soviet Union, U.S. sanctions against Latin American nations for human rights violations, and British sanctions against Argentina during the Falklands War. Martin emphasizes that credible commitments gain international co-operation, and she concludes that the involvement of international institutions and the willingness of the main sender to bear heavy costs are the central factors influencing credibility.