In a 1980 interview, Gabriel García Márquez told The New York Times that he had spent three years writing a book about life in Cuba under Fidel Castro. But, he said, “now I realize that the book is so critical that it could be used against Cuba, so I refuse to publish it.”

In view of the Colombian author’s past concern for the victims of Latin America’s authoritarian regimes, it seems likely that what he called a “very harsh, very frank book” addressed Castro’s systematic repression of dissent: the rigged trials behind closed doors, the abysmal “reeducation” camps, the long prison sentences. Castro’s methods may have seemed relatively tame when compared with the mass slaughter of civilians by US-backed regimes throughout the region, for example in Guatemala. Yet as the cold war ended, these dictatorships gradually gave way to civilian rule, and the Castro government was left standing as the only one in the hemisphere that continued to repress virtually all political dissent. García Márquez’s book remained unpublished.

The fact that Latin America’s most renowned writer would censor himself in this way may actually say more about the plight of Cubans under Castro than anything in his manuscript. For the notion that to criticize Cuba is to abet its more powerful enemies was, for Fidel Castro, the key to achieving what his prisons alone could not—ensuring that his critics on the island remained isolated and largely ignored.

For years, many believed that the last thing keeping the region’s democratic tide from sweeping across Cuba was the unique force of Fidel Castro’s character—the extraordinary combination of charisma and cunning with which he inspired and corralled his supporters, provoked and outmaneuvered his enemies, and projected himself onto the big screen of world politics. Under his leadership, Cuba had made impressive gains in health care, education, and the eradication of extreme poverty. But the promise of the Cuban Revolution had been undercut by years of chronic deprivation, exacerbated by the US embargo, and brought to the brink of collapse by the dissolution of the Soviet Union, which had propped up the island’s economy for decades. Democracy would come to Cuba—the thinking went—as soon as Fidel Castro was no longer standing in its way.

Then in June 2006, his health failing, Castro was forced to step down formally after nearly five decades in power. And nothing happened. No popular uprising in the streets, no Party shake-up, no coup. Instead, his younger brother, Raúl, took up power and, though lacking Fidel’s charisma, was able to keep the country running smoothly. Within months, it seemed clear that Cuba’s single-party system could continue without Fidel at the helm.

Some still held out hope that Raúl Castro would begin a process of political reform, a Cuban perestroika. Those looking for signs of…