Now that all but a handful of Haitians have left the U.S. naval base at Guantanamo Bay in Cuba, administration officials and immigration experts agree that the solution to this refugee crisis marked an important change in U.S. policy for at least one reason: It was temporary.

In the past, U.S. leaders usually had to choose between two unattractive alternatives when faced with a swarm of people seeking shelter from political harm. The government could either welcome them all into the country forever or coldly turn them all away.

In response to the exodus of Haitian boat people last summer, Clinton administration officials devised a new set of legal principles and policy concepts for a "safe haven" alternative that allowed the United States to offer protection to a large number of people -- but only for as long as they needed it.

More than 20,000 Haitians ended up at the tent city in Guantanamo last summer, and about 16,000 voluntarily returned home after the U.S. military intervention returned Haitian President Jean-Bertrand Aristide to power in October. Almost all of the remaining 4,000 were forcibly returned to Haiti in January in a controversial ending for the program.

The United Nations High Commissioner for Refugees publicly criticized the administration for conducting "cursory" screening of the Haitians who did not want to go home, and the U.N. office complained that the internationally accepted standards for determining refugee status had not been observed.

"Our interviewers were instructed to go beyond the international standard in deciding who we still needed to protect," said Alex Aleinikoff, general counsel for the Immigration and Naturalization Service (INS).

Some 82 Haitians have been allowed to remain at Guantanamo pending further review of their cases. They include women who were gang-raped by paramilitary thugs and people who witnessed the murder or torture of relatives, Aleinikoff said.

"Overall, I think many people see safe haven as a laudable achievement despite some concerns about how it was ended," said Peter H. Schuck, a professor at Yale Law School. "Temporary protection and repatriation to safe conditions is always the best solution to a refugee crisis."

Administration officials are confident that for the first time they have a model for just such an operation.

"We are moving toward a law of safe haven that sets a very low standard for people coming in and protects them until conditions change and even then ensures that people are not returned to face harm," Aleinikoff said.

Now the question is whether the safe haven solution can ever be duplicated.

"Every situation is unique, but when we face another crisis in the future, safe haven will be immediately considered as an option," INS Commissioner Doris Meissner said.

And another crisis seems inevitable. Political turmoil somewhere in Mexico, Central America or the Caribbean readily could produce an outpouring of people.

"The administration deserves credit for finding a new way of dealing with this kind of episode because there will be more of them," said David A. Martin, an expert on refugee policy at the University of Virginia Law School. "The problem is there may not be many other episodes that lend themselves to this approach. The key is knowing that you are dealing with a short-term situation."

Safe haven for the Haitians proved to be short only because the United States used its armed forces to end the cause of the exodus. If there had been no intervention, an even greater number of Haitians might still be at Guantanamo.

"In Haiti, a solution was on the horizon from the time the safe haven program started," Martin said. "Cuba shows you what happens when there is no certainty of a solution."

Within weeks of setting up the safe haven camp for Haitians at Guantanamo last summer, the administration decided it would send the growing number of Cuban rafters there under similar legal circumstances. Like the Haitians, the Cubans were told they would have no chance to seek admission to the United States from Guantanamo.

But the administration has no publicly stated commitment to changing the political situation in Cuba as it did in Haiti. About 30,000 Cubans have spent nearly five months in the camps at Guantanamo and in Panama with no end in sight.

"Safe haven becomes indefinite detention if there is no plan to deal with the causes of their flight, and, as with the Cubans, that can become an explosive situation," said Harold Koh, a professor at Yale Law School.

Both the Cuban and Haitian crises last summer presented the Clinton administration with similar domestic political problems that propelled the search for a new policy that would not involve a highly visible surge of new immigrants.

"A major problem with permanent resettlement of refugees during a crisis is that you run the risk of being overwhelmed and losing your public support, and then you are forced to shut down the operation entirely," Meissner said.

Safe haven, Aleinikoff said, "is a move from resettlement to rescue," offering protection to more people than would have been possible with permanent resettlement.

It was a change that has been developing over time, Meissner noted. "By tradition, we are a nation of permanent resettlement, but in practice we have become a nation of first asylum," she said. Instead of identifying fugitives from tyranny far away, the United States now faces a constant flow of people arriving at its shores or borders seeking sanctuary.

The process of screening refugees for permanent resettlement proved an "inappropriate tool" for the flows that have come northward from Central America and Haiti in recent years, Meissner said, adding, "In a changing world, you need new models."

In 1990 Congress created a new model by allowing illegal immigrants from El Salvador to remain here under temporary protected status until the war in their homeland ended. But the measure was extended repeatedly even after the fighting stopped. Even when the Clinton administration formally ended the program at the start of this year, it acknowledged that those who stayed on would not be forcibly removed.

The safe haven concept avoids some of those problems because the havens are outside the United States and beyond the jurisdiction of American courts with their lengthy appeal processes. But that also poses a major limitation.

"This idea would work best if other nations in the region permitted substantial safe haven establishments on their territory," said Schuck of Yale University.

Despite extensive diplomatic efforts, however, the United States was unable to win commitments from any of its neighbors to establish large safe haven camps. Panama was the only exception in agreeing to take up to 10,000 Cubans, but it put a six-month limit on its welcome. CAPTION: DORIS MEISSNER