DescriptionThe decisions made by President John F. Kennedy during the Cuban missile crisis in October 1962 likely prevented the outbreak of World War III. Understanding the president’s possible motivations behind those decisions, including any possible religious motivations, is key to a more complete understanding of the eventual peaceful resolution of the crisis. Kennedy’s was a complex religiosity from childhood, further complicated by anti-Catholic prejudice and his own assertions of the firm separation of church and state during the 1960 presidential campaign. While keeping his religiosity a private matter, those closest to the president documented their memories of his words and actions during the crisis. Using these recollections, it is possible to get a sense of what things the commander in chief may have taken into consideration when deciding which course of action to pursue. From statements made by the president to the manner of his interactions, evidence of his attitudes and concerns during the crisis provides inferences into the character of his conscience. These inferences suggest that Kennedy’s decisions may have been influenced by the empathy he was able to feel for others, that he may have been guided by a conscience of peace formed, in part, by his religious faith, and that he may have weighed his actions using tenets of the Catholic Church, particularly the four cardinal virtues: prudence, temperance, justice, and fortitude. The papal encyclical issued by Pope John XXIII in April 1963, Pacem in Terris, lays out as official Church doctrine the need for universal peace through Catholic virtues such as justice and truth. This encyclical appears to echo some of the attitudes that, according to those closest to him, President Kennedy took on during the Cuban crisis, further supporting the idea that Kennedy’s faith influenced his decisions.