More than two-thirds of Cuba's 11 million population have been born since Fidel Castro came to power in 1959. Yesterday's news that he is to step aside because of illness for the first time since then comes as a major political surprise, since Castro and the regime have become inseparable.
Although this is described as a temporary transition to the senior vice-president - his brother Raul Castro - inevitably it raises questions about the regime's sustainability without its charismatic leader, should he fail to recover from his operation for intestinal bleeding.
This was brought on by his exceptionally intensive recent schedule, during which he addressed the Mercosur conference in Argentina, visited other places there, including Che Guevara's childhood home, and attended another round of revolutionary anniversaries in Cuba on his return. Castro's phenomenal political energy has continued into his old age - he is nearly 80. It is remarkable that this is the first occasion he has had to stand aside. If he returns to office, his temporary absence will surely provoke a review of the power structure he personifies.
It is highly centralised. Castro is head of state, of government, of the armed forces and of the communist party. Within a one-party system, this is a formidable concentration of power and authority. Notwithstanding its repressive and coercive record, the regime has been continually legitimised by internal achievements, external support and perpetual confrontation with the United States. The transition at the end of the Cold War was weathered by substituting Chinese and European credit and trade for the heavy dependence on the Soviet Union. More recently, Castro has forged a close working relationship in Latin America with the Venezuelan leader, Hugo Chavez, based on practical and popular health and educational programmes as well as subsidies.
Social egalitarianism within Cuba has maintained popular support, despite the failure to introduce economic or political reforms. Raul Castro has a record of being a pragmatic innovator, willing to learn selectively from the Chinese. He may take this opportunity to initiate such change. As always, the regime justifies its authoritarianism by the need to confront US hostility and with dire warnings that all its achievements would be lost were it to be overthrown. In contrast to the Clinton administration's efforts to encourage a gradual opening and warming of relations, President Bush has put himself squarely behind the counter-revolutionary Cuban exiles based in Miami. The tone and nature of this confrontation is not changed by the transition from one Castro to the other.