This fascinating book argues that the growth of international law changed how powerful states decided to intervene in weaker ones. Examining cases of U.S. interventions in Latin America during the Cold War, Poznansky studies overt interventions, such as the deployment of U.S. troops to the Dominican Republic in 1965, and covert interventions, such as the Bay of Pigs invasion in 1961. He notes that great powers in the era before 1945 rarely felt obliged to operate in the shadows. This changed after 1945, according to Poznansky, with the UN Charter, which enshrined the principle of nonintervention in treaty law, a principle that was soon adopted by far-flung regional bodies. International law altered the calculus of great powers. Resorting to covert forms of intervention allowed the United States to evade damage to its credibility and charges of hypocrisy. In chapters on U.S. interventions in Chile, Cuba, the Dominican Republic, and Grenada, Poznansky presents archival evidence of officials worrying—to various degrees—about violating international law, pushing decision-makers to pursue covert rather than overt military action. International law is less a formal constraint on the conduct of military policy than part of a complex normative environment in which states operate.