The Mariel Boatlift of 1980 marked the beginning of the third great wave of Cuban immigration to the United States. Between April and October, thousands of seacraft of all kinds were sent to the Cuban port of Mariel to transport some 125,000 friends and relatives back to the United States. The number of immigrants immediately overwhelmed the ordinary provisions of the Refugee Act (April 1, 1980), and the poverty and questionable background of many of the migrants led to a marked increase in American hostility to immigration. Until the 1970s, Cuban immigration policy of the United States was driven by an ideological commitment to deter communism and thus was not subject to the restrictions of ordinary immigration legislation. Beginning in 1970, however, the governmental consensus in favor of Cuban exemptions began to break down. By 1980, the new Refugee Act required Cubans to meet the same “strict standards for asylum” as other potential refugees from the Western Hemisphere, placing escapees in the same category as Haitians (see Haitian immigration), who had been arriving illegally in large numbers throughout the 1970s. Facing a weak economy, on April 20, Cuban president Fidel Castro opened the port of Mariel to Cuban emigrants after seven years of migratory suspension. Castro encouraged emigration by common criminals so as to rid the country of “anti-social elements.” Within five months, more than 125,000 Cubans had been transported to the United States, including 24,000 with criminal records. At first the marielitos were treated as refugees, but by June 20, the government had enacted sanctions against those transporting Cuban migrants and had confirmed that Cubans would be coupled with Haitians as “entrants (status pending),” rather than as refugees. Occasional violence by Cuban detainees upset by their inability to gain formal immigrant status further undermined the perception of Cuban migrants in the public mind. Fearing both an exodus of skilled technicians and deterioration of relations with the United States, on September 25, Castro closed the harbor at Mariel to emigration. Negotiations by the administrations of Jimmy Carter and Ronald Reagan in the wake of the Mariel Boatlift led to a December 1984 migration agreement that came close to normalizing immigrant relations between the two countries. Cuba agreed to accept 2,746 “excludable” Mariel Cubans, and the United States agreed to issue 20,000 annual “preference immigrant visas to Cuban nationals.”