Snagged from the US infantry Museums page.
Troubles in the Dominican Republic began in 1961, when long-time dictator Rafael Trujillo was assassinated. Trujillo had been a brutal leader, but his strong anticommunist stance helped him retain the support of the United States. His death led to the rise of a reformist government headed by Juan Bosch, who was elected president in 1962. The Dominican military, however, despised Bosch and his liberal policies. Bosch was overthrown in 1963. Political chaos gripped the Dominican Republic as various groups, including the increasingly splintered military, struggled for power. By 1965, forces demanding the reinstatement of Bosch began attacks against the military-controlled government. In the United States government, fear spread that “another Cuba” was in the making in the Dominican Republic; in fact, many officials strongly suspected that Cuban leader Fidel Castro was behind the violence. On April 28, more than 22,000 U.S. troops, supported by forces provided by some of the member states of the Organization of American States (a United Nations-like institution for the Western Hemisphere, dominated by the United States) landed in the Dominican Republic. Over the next few weeks they brought an end to the fighting and helped install a conservative, non-military government.