The immense secondary literature on the Cuban missile crisis of October 1962 tends to overlook the U.S. government's promotion of a case in international law to legitimize and generate support for the naval blockade of Cuba. This article explores the development and presentation of the legal case and then gauges its success by looking at the response of various non-Communist governments. Those governments endorsed U.S. policy despite, not because of, the U.S. legal case, which they found highly questionable. The analysis here draws extensively on archival sources as well as on the latest published research and presents a fresh contribution to the historiography about the most dangerous confrontation of the Cold War.