He has been in power so long that Fidel Castro is barely noticed now as the anachronism he has become: an absolute ruler of a one-party state, a beached survivor of an ideology long swept away elsewhere, a man who has kept the modern world at bay while corruption eats away at his island fortress. Cubans rarely break the taboo and speculate on Cuba after Castro. Most, with reason, do not dare. But suddenly, only two weeks before the planned lavish celebrations of the dictator’s 80th birthday, they have been jolted into an uncertain future: after 47 years of untrammelled personal rule, President Castro has suffered a serious illness and handed over power, albeit temporarily, to his 75-year-old brother Raúl.

The prospect of Fidel Castro’s death or disability has convulsed the Caribbean. The long US blockade, the regional political balance and Havana’s predictable backing for any anti-American insurgency have all been fixtures of a stalemate that has been a determining factor in US regional policy. Cuba may have only 11 million people, and a stricken economy overly dependent on sugar and raw materials. But it has long been seen in Washington as an ideological dagger pointed at the Western hemisphere. It was over this island that the world came closest to nuclear Armageddon. Cuba’s defiance and the clout of Cuban exiles influence US domestic policy. What happens now will be watched in Washington and Miami as closely as in Havana.

Both on the island and abroad, people are preparing for change. Few doubt that the communist system will die with Señor Castro. The collapse of the Soviet Union made its continuation ever more precarious — and cautious market reforms a few years ago so quickly began to unravel the entire structure that the frightened Government quickly backtracked. For now the economy is in stasis. But entrepreneurs know well the pent-up demand for change, for imports, luxuries and links to the outside world, and are already preparing to seize the moment when the US embargo is lifted.

Some fear that the country could quickly return to 1959, becoming a playground of the American rich, where weak governments are domi-nated by gambling interests and corrupt businessmen. There is, indeed, a danger of change coming too explosively and of a new mafia taking advantage of a communist collapse, as in much of Eastern Europe. But that is to ignore everything that has happened since the fall of Batista. Cuba is more robust now. For all the repression, religious persecution and assault on human rights, the Cuban people have three advantages on which to build a future: an education system that has given them literacy and qualifications; a credible national health system; and a cultural pride, seen in the flowering of the arts and music.

The challenge now is how to plan the inevitable transition without triggering collapse and chaos or fresh repression. The Bush Administration appointed a Commission for Assistance to a Free Cuba in 2003 to hasten political change, setting aside $80 million to boost democracy. The US will certainly find vast sums to satisfy post-Castro expectations. Within Cuba, officials must also be looking at ways to survive the change. Rumours abound and hopes are rising. But nothing should be assumed. Señor Castro has survived past health scares. He could yet stagger on.