For most of President Ronald Reagan's first term, U.S.-Cuban relations were frozen. But late in 1984, an agreement was reached between the two countries. Cuba would take back more than 2,700 Cubans who had come to the United States in the Mariel because of criminal or psychiatric disqualification. Castro canceled the agreement when the U.S. began the Radio Marti broadcasts in May 1985 to bring a non-Communist viewpoint to the Cuban people.

With the collapse of communism in eastern Europe, Cuba's foreign trade plummeted as did aid from Russia, producing the worst economic crisis in the island's...