The survivors of the Bay of Pigs have taken back their flag.

Fifteen years ago this month, when President John F. Kennedy welcomed the 1,113 returning prisoners from Cuba in an emotional ceremony at Miami's Orange Bowl, he took custody of' the battle flag of the ill-starred Assault Brigade 2506 with the promise that "this flag will be returned to this brigade in a free Havana." But since then, the army of CIA-trained Cuban exiles has merged indistinguishably into America. New York lawyer James B. Donovan, who negotiated their ransom from Fidel Castro's jails in exchange for $53 million worth of drugs, medical equipment and baby food, died of cancer in 1970. Richard Bissell, the CIA deputy director who masterminded the invasion, has retired from the government. The U.S. is inching toward renewed relations with Castro's Cuba. And plans are being made to exhibit the battle flag in Miami.

Bissell, now 68, hasn't had any contact with the Cubans since he resigned from the CIA during the shake-up that followed the invasion fiasco, though he says that "I've wondered what happened to them." After a brief stint with the federally funded Institute for Defense Analyses, he became a business consultant, first with United Aircraft and now with his own company in Farmington, Conn. He decries what he calls the "gross oversimplifications" of the invasion's failure. "Some people say if it hadn't been for Kennedy calling off a particular air strike, it would have succeeded," Bissell says. "Others say it was doomed no matter what. I disagree with both. I think it would have had a chance of success--but only a chance--if the President had taken a strong stand. There were a lot of reasons why it failed, but I think we gave it a good college try."

Monument: Today, the men of Brigade 2506 stay in touch with their cause--and each other--through the Bay of Pigs Combatants Association, which has headquarters above a community center in Miami's "Little Havana" section. The association sponsors protest marches, pickets conventions that recognize delegations from Cuba and each year commemorates the anniversary of the invasion with a rally around the Miami monument dedicated to the Bay of Pigs "martyrs." (In Cuba, the invasion is celebrated two days later, on the date the invaders were defeated.)

Two years ago, the association successfully sued the U.S. Government to get the brigade flag back. "President Kennedy has gone to his reward," the suit argued, "Havana is not free, and the banner of Brigade 2506 gathers dust in some museum." Arrangements are now being made to put the banner on display in a theft-proof case at a Miami shrine to Our Lady of Charity, whom the Cubans consider their patron saint.

'On Our Own': The association has recently stepped up attempts to foment opposition to Castro within Cuba, a policy that has created a split in the group's ranks. "We're definitely more active and aggressive than some people wanted the brigade to be," says 37-year-old president Roberto Carballo, who is part owner of a Florida export company. "Many people wanted the brigade to stand off and be sleeping until the Americans called for us again and asked for our support. But we think we should be doing it on our own." Though he voices his opposition to any terrorism on U.S. soil, Carballo acknowledges that the association is planning raids against Cuba "to kill Fidel Castro and the primary forces around him." In October, four members--including the brigade's military chief--were indicted on Federal charges of' conspiring to launch a raid against Cuba in violation of U.S. neutrality laws. Customs agents in Miami seized three boats, one of them loaded with automatic weapons and camouflage uniforms.

Raul Masvidal, 35, who made a career in banking after the invasion and was recently named chairman of the board of the Biscayne Bank of Miami, says he is among those who have become "disconnected" with the association, though be still pays his dues. "I don't see any practicality in going to cheering sessions," he explains. "I'm 35 now. I have a family. I didn't have a family when I was 18." Masvidal has no regrets about taking part in the invasion, however. "I think it was the closest we have come to liberating Cuba in seventeen years," he says. "Today I feel totally satisfied with myself that I did what I could for my country." But, he adds, whereas Castro was once "just another dictator," now he is firmly entrenched with Soviet support and "there's no question that he's beaten us--he's won so far."

Those who remain active in the Bay of' Pigs Combatants Association see the liberation of Cuba as an ongoing struggle, and remain fiercely dedicated to a cause that looks increasingly remote in view of' the growing rapprochement between Washington and Havana. "My feeling and the feeling of most Cubans," says 42-year-old association treasurer Fidel Fuentes, "is that if the U.S. Government doesn't want to help us overthrow Castro, the least they could do is let us do it and don't interfere. My duty to my country is to see it free of Communism, and I will try to accomplish it. You are just a grain of sand, but when you join many grains of sand, you make islands, continents, right?" Looking back on the Bay of Pigs invasion, Fuentes says: "I am not bitter. I am not angry. There is a hope that Cuba will be free--sometime."

EILEEN KEERDOJA