The TIME 100

Cuba without the inimitable Fidel? That had been unattainable for 10 American Presidents and unimaginable for generations accustomed to his strutting anti-"Yanqui" ways. But with Castro's health in question, his younger brother Raúl, the world's longest serving Defense Minister, has smartly consolidated his claim as Fidel's most likely successor. He could even prove to be a figure as historic as Fidel—but if so, it will be for guiding Cuba away from many of his brother's tragic legacies.

Raúl, 75, "provisionally" succeeded the gravely ailing Fidel last July, promptly demonstrating a laid-back style and commitment to pragmatic economic policies. A merciless executioner during the revolution's early days, he later enforced cruel purges and crackdowns. He has remained a staunch Stalinist ally of the Kremlin. But he has also stated his willingness to negotiate with Washington to end the enduring stalemate in relations—something Fidel has always shied away from—and recognizes the need to stimulate the stagnant economy, engage Cuba's disaffected youth and modernize the discredited communist system. The challenge will be doing it without shaming Fidel's memory. But chances are that after being consigned to the shadows for the past 50 years, Raúl yearns to be remembered for his own historic contributions.

Latell is the author of After Fidel: Raul Castro and the Future of Cuba's Revolution