Fidel Castro's role in the history of Cuba is nicely summed up in the way the news of his retirement spread Tuesday. It was a huge story that flashed around the world as soon as it was posted on the online edition of Granma, Cuba's Communist Party newspaper. But Cubans themselves were unlikely to have seen that initial report, because it was early morning, and they are barred from having Internet access in their homes.

Cubans have known many such paradoxes during their 49 years under Castro, the only president their country has had since he led its revolution against the Batista regime in the 1950s. They have accomplished notable successes -- with literacy and infant mortality rates better than ours, and a life expectancy nearly as long -- while laboring under a heavy-handed dictatorship that punishes political dissent and unconscionably limits freedom of expression. Once the golden child of Soviet client states -- a scant 90 miles from the hated America -- Cuba suffered the Soviet decline and stood stubbornly as a Cold War orphan after communism collapsed.

Through all those changes, the unmovable force in Cuba's life was Castro. From the very first, he and his regime have withstood an amazing array of challenges: assassination plots, the Bay of Pigs invasion, the Cuban Missile Crisis, the American-led trade embargo and the loss of Soviet aid that had helped it withstand that embargo. And for every challenge faced there was an opportunity missed -- in trade, tourism, cultural exchange and a hundred other areas. Intransigence on both sides was preserved at a heavy cost. Estimates suggest that the embargo costs U.S. companies $1.2 billion a year. The cost just to Minnesota was hinted at in 2002, when Gov. Jesse Ventura led a quixotic trade mission to a country with which trade is mostly illegal. Despite that obvious stumbling block, the effort demonstrated a pent-up demand for commerce and other relations.

President John F. Kennedy, who ordered the embargo in 1962, was careful first to lay in a supply of Cuban cigars (www.startribune.com/a4032). Just as the embargo worked against his personal interest, it works today against the national interest. Trade can be the United States' most potent weapon in subverting a dictatorship, because it builds person-to-person relationships that can bypass the controls of government. Likewise, enforcing a trade ban can help prop up a dictatorship by giving it a villain to blame for its shortcomings. It's past time the United States removed that prop, and Castro's retirement offers an opportunity to do so.

Once that barrier is removed, the United States and Cuba should proceed to the next logical, overdue step: diplomatic relations. If the United States can recognize Vietnam and China, there's no reason to snub little Cuba -- except, of course, the political clout of anti-Castro Cuban exiles in Florida. That community has wielded too much influence for too long. Now it should set aside its animosity and answer President Bush's call to help Cubans build the institutions of democracy. If Cuba is to move toward something resembling popular rule, it will need an infrastructure -- independent courts, an unfettered media, academic freedom at colleges and universities -- to support it.

Castro's Cuba is a textbook example of a country governed through a cult of personality, such as Hugo Chavez dreams of creating in Venezuela and the delusional Kim Jong-il thinks he has achieved in North Korea. It is the sort of rule that, deprived of its leader, turns to a relative as next best choice. That's what appears likely to happen in Cuba as Castro's brother, Raul, takes the reins. We hope that Raul's tenure in office is short and that his country begins the difficult process of democratic reform.

Even in retirement, Fidel is likely to remain the most prominent feature of Cuba's political landscape. He is, after all, the most resilient national leader of two centuries. Those who have waited long and eagerly for a post-Castro Cuba should relax; until we read not a retirement notice but an obituary, there won't be any such thing.