On June 4,1943, the day of the military coup that overthrew the government of President Ramón S. Castillo, it seemed highly unlikely that Juan Domingo Perón would emerge three years later as an elected president of the Republic, drawing most of his support from the members of the organized labor movement. First, Perón was only a colonel, and was outranked by many of the officers associated with the coup against Castillo. Second, he was virtually unknown outside the ranks of the armed forces. Third, he apparently had had relatively-little contact before the events of June 4,1943, with the kind of people who were subsequently to become his most loyal supporters.