AP Photo

Last week, to mark the 51st anniversary of Fidel Castro's revolution, a couple of thousand Cubans assembled on a plaza facing the American diplomatic mission in Havana. They danced to amplified salsa music and paid little heed when a man on stage tried to excite them with shouts of "Viva Fidel! Viva Raúl! Viva la Revolución!"

It was a far cry from the days when vast crowds gathered to hear Castro deliver extended rants against imperialism and promise his people a glorious future. Today Castro is frail and out of sight. His elderly brother, Raúl, did not turn out for this year's anniversary either. Their sclerotic immobility aptly reflects the collapse of hope that defines Cuba today.

Vestiges of revolutionary enthusiasm survived into the 1980s, when...