Castro's Cuba begins to align itself with the USSR, beginning a heavy, decades-long flow of migration to the U.S. in order to avoid Communism.
The flow of Anti-Communist Cubans to the U.S was composed primarily of mid-to-upper class Cubans initially, however later the migration expanded to poorer Cubans as well.
Rumors of the Communist government sending Cuban children away to be indoctrinated in the USSR began to spread throughout Cuba. This led to an American Catholic group in Miami flying more than 14,000 unaccompanied (mostly mid-to-low class) Cuban children to the U.S.
Granted Refugee status to incoming Cubans
After an incident at the Peruvian Embassy, the port at Mariel was opened to any Cubans with a means of leaving the island. Nearly 125,000 Cubans migrated in the summer of 1980. The migration was cut off when the U.S. discovered that the incoming immigrants included released criminals and mental patients. (NOTE: the majority were average Cubans. According to a 1991 Congressional report, criminals were roughly 25%)
Adjustment to 1966 CRAA, the gist of which is that Cubans found at sea would no longer be admitted to the U.S. and only Cubans that had reached U.S. soil would be able to pursue Legal Permanent Resident status, citizenship, etc.