 In late 1945 , Castro began studying law at the University of Havana . Admitting he was " politically illiterate " , he became embroiled in the student protest movement : under the regimes of Cuban Presidents Gerardo Machado , Fulgencio Batista and Ramón Grau there had been a crackdown on protest , with student leaders being killed or terrorized by gangs . This led to a form of gangsterismo culture within the university , dominated by armed student groups who spent much of their time fighting and running criminal enterprises . Passionate about anti @-@ imperialism and opposed to U.S. intervention in the Caribbean , Castro joined the University Committee for the Independence of Puerto Rico and the Committee for Democracy in the Dominican Republic . During an unsuccessful campaign for the presidency of the Federation of University Students ( Federación Estudiantil Universitaria - FEU ) , he put forward a platform of " honesty , decency and justice " and emphasized his opposition to corruption , which he associated with U.S. involvement in Cuba . 
