Carter later said he was misunderstood, and on May 14 ordered the Coast Guard to stop all Cuba-bound boats. By the end of June, the flow of arrivals had slowed to a trickle, but the problems continued.

It took two months for the administration to decide to treat the arrivals as asylum seekers rather than refugees, to avoid setting a precedent that foreigners arriving by boat would be considered refugees.

State Department officials, meanwhile, argued that the boatlift was largely a domestic issue, while other U.S. departments wanted State or the White House to take the lead.

``This was a unique emergency that was half foreign policy and half domestic policy, and involved a whole bunch of people who were not accustomed to working together,'' said Pastor, now a professor at American University in Washington.

Carter initially refused direct negotiations with Castro but later sent to Havana Pastor, then Latin America director at the White House's National Security Council, and Peter Tarnoff, executive secretary at the State Department.

Mariel ``was totally mishandled,'' Engstrom quoted Stuart Eizenstat, Carter's chief domestic policy adviser, as saying.

In the end, the boatlift helped spike what was the most determined effort by any U.S. president in half a century to resolve U.S.-Cuba hostilities.

``We should attempt to achieve normalization of our relations with Cuba,'' Carter wrote in a secret Presidential Directive -- in essence an order to his administration to work toward that goal -- soon after he entered the White House.

He lifted all restrictions on U.S. travel to Cuba, including tourism, and exchanged diplomatic missions known as Interests Sections in Havana and Washington.

Carter negotiated a 1977 agreement that delineated territorial waters and fishing rights, and agreed to take more than 3,000 former political prisoners released by Castro.

But he failed to persuade Cuba to pull its troops out of Angola -- one of Carter's key goals -- and the last Cuban soldier did not leave Africa until 1991.

An analysis of the Mariel crisis carried out by the Reagan administration concluded that Mariel ``destroyed any prospect of improved bilateral relations under President Carter.''