MIAMI, May 23 -- Political intrigues don't come any more epically scaled than this one: the future of Cuba after the inevitable death of Fidel Castro, the world's longest-reigning head of state and an American government nemesis like few others.

The singular obsession that consumes the exile community here only grows more passionate as Castro, 78, ages. It tends to crescendo at the tiniest hint of vulnerability, such as the fall last year that broke his kneecap and arm, erupting in banner headlines and talk-radio vitriol in Miami. Castro has named his brother Raul, who is five years younger, to succeed him. But a Cuban exile daredevil who once flew missions over the island to drop human rights leaflets wants to get in the way.

Jose Basulto, president of Hermanos al Rescate, or Brothers to the Rescue, plans to announce Tuesday afternoon that he is offering $1 million for information leading to the indictment of Raul Castro on charges of drug trafficking and of murdering four Brothers to the Rescue pilots and passengers whose two small planes were shot down by Cuban MiG fighter planes off the island's coast in 1996.

The offer is intended to publicly pressure the U.S. government into resurrecting investigations of long-standing claims of criminal wrongdoing. But -- more important -- it also is intended to weaken Raul Castro and his allies politically and to complicate or even make illegal his succession.

"It would throw a wrench in the machinery," Basulto said of the hoped-for indictment.

Basulto already has enlisted influential figures. Guy Lewis, a former U.S. attorney in Miami who prosecuted Panamanian strongman Manuel Noriega and was instrumental in the indictment of three Cuban airmen for the Brothers to the Rescue shoot down, said in an interview Monday that "there is significant evidence" in the public record to warrant indicting Raul Castro in connection with drug trafficking and the shoot-down or, at the very least, to prompt law enforcement to further investigate.

Evidence surfaced in the Brothers to the Rescue investigation, Lewis said, that Raul Castro was at the top of the chain of command that ordered the civilian group's planes shot down. During the Noriega trial, Lewis said, witnesses testified that Raul Castro facilitated cocaine smuggling to the United States. Drug kingpin Carlos Lehder has implicated Raul Castro in testimony in other cases. And a former hit man -- now in a Colombian prison for a political assassination -- who worked for drug kingpin Pablo Escobar told Spanish television network Television Espanola this month that Raul Castro was the Medellin cartel's contact for drug shipments to Miami.

Some have questioned the credibility of the former traffickers. A spokeswoman for the U.S. attorney's office in Miami declined to comment on the allegations.

The reward money for information leading to Raul Castro's indictment would come out of a $1.7 million judgment against the Cuban government awarded in January to Basulto, whose plane escaped the same MiGs that shot down his colleagues. Basulto plans to try to collect the money from the $192 million in seized Cuban assets held by the U.S. Treasury, which awarded $93 million in 2001 to the families of three Brothers to the Rescue members.

Indictments of Raul Castro have been considered before. The Miami Herald reported in 1993 that federal prosecutors had drafted an indictment accusing him and other top Cuban officials of helping the Medellin cartel funnel 7.5 tons of cocaine to the United States through Cuba. For months, passions were stirred by reports in various media outlets that an indictment was imminent, but no charges were announced.

Indicting a foreign leader, though difficult, is not impossible. When former Chilean dictator Augusto Pinochet was arrested, the British House of Lords said he was not protected by head-of-state immunity because the allegations against him involved torture. In the U.S. system, indictments of foreign leaders are political, as well as law enforcement decisions, said Michael P. Scharf, an international law expert at Case Western Reserve University in Cleveland.

"It's in the discretionary hands of the executive branch," he said.

The Bush administration has tried to foster good relations with the exile community, but Scharf said, "I can't even imagine what an international firestorm" an indictment of Raul Castro would set off. Basulto's legal team believes emphasizing the Cuban government's designation by the United States as a state sponsor of terrorism would provide the extra impetus in the post-Sept. 11, 2001, political climate that might not have been there before.

"The concept of terrorism and terrorist governments has changed," said Silvia Pinera-Vazquez, one of Basulto's lawyers. "This is a threat that's 90 miles away. Anything we can do to weaken that state makes us safer."

Indicting a foreign leader does not necessarily give the United States the right to incarcerate him, Scharf said, but it could subject the leader to arrest and extradition to the United States during his travels, effectively making him "a prisoner in his own country."

The proposed indictment of Raul Castro is a piece in a much larger, and often disjointed, movement aimed at one of the signal moments in recent history: the end of Fidel Castro's reign in Cuba, which began with his revolutionary takeover in 1959. Nettlesome questions about the property rights of exiles and of enemies of the Castro regime in Cuba -- as well as the economic, political and diplomatic tangles that may ensue -- are endlessly debated here. The University of Miami even has a team of researchers, known as the Miami Transition Project, dedicated to developing solutions to avert the chaos that has accompanied so many power shifts in other Latin American nations, particularly considering that several hundred thousand Cuban exiles are only a short boat ride away in Miami.

Jaime Suchliki, the project's director, expects that martial law will be declared in Cuba as soon as Fidel Castro's death is announced and that U.S. law enforcement agencies will swing into high alert. "The party is going to be in Miami," he said. "This town is going to be paralyzed for two days."

The dumbest thing for the exile community to do, Suchliki said, would be to try to install a political leader in Cuba, rather than patiently awaiting gradual democratic changes. Basulto, with his dive-bombing days behind him, might be just the sort of celebrity exile who some think could generate a following to become the leader -- or at least a high-ranking official -- in a post-Fidel Castro Cuba. Basulto, though, says he's not putting up $1 million to get into office, but to keep Raul Castro out.