HAVANA — Fidel Castro says he won't stand in the way of younger people who can lead Cuba, but he also insists on being "of consequence" until the end of his life. So it goes with the ailing 81-year-old — eager to see others keep up the revolution but reluctant to let go of power.

The real question is not whether Castro will retire but whether it will make much difference in Cuba.

The answer: probably not, as long as he's alive.

Despite much excitement this week over one ambiguous sentence in a letter about global warming in which Castro indicated he will not hold back Cuba's younger leadership, Castro already has settled into a kind of reflective semiretirement.

He hasn't appeared in public in the 17 months since having intestinal surgery and naming his younger brother Raul, now 76, as Cuba's "provisional" president.

But island life has hardly changed under his brother, and the elder Castro has retained a vibrant role in Cuban politics, penning several essays a week and showing up sporadically in official photographs and prerecorded messages.

"The succession in power from Fidel Castro to his brother Raul appears to be a done deal, but the evolution away from Fidelismo will start only upon the death of its namesake," wrote Peter DeShazo, a former U.S. State Department official who runs the Americas program at the Center for Strategic & International Studies in Washington.

"When that happens, Raul Castro steps out from behind the shadow of his flamboyant sibling and the beginning of a transition process to a new order in Cuba may commence," DeShazo said in a commentary released Tuesday.

After the Castro brothers, few younger leaders stand out despite the fact that Fidel has made a priority of nurturing fresh talent to carry on Cuba's communist revolution.

Vice President Carlos Lage, 56, is Cuba's de facto prime minister and a strong possibility to be No. 2 if and when Raul Castro permanently assumes the presidency. Foreign Minister Felipe Perez Roque, 42, could be another candidate for vice president or play a key role in the politically powerful Communist Party, which Castro also now heads.

These younger leaders will be vital in any future reconciliation with the United States, which is barred by the 1996 Helms-Burton law from normalizing relations with Cuba so long as either Castro brother is involved in government. The countries have no diplomatic relations, and Cuba remains under a U.S. trade embargo imposed 45 years ago.

The elder Castro has raised the possibility of formally retiring from office before. He declared in an Oct. 20, 2004, speech that if he becomes too sick to lead, he'll call the Communist Party "and tell them I don't feel I'm in condition ... that please, someone take over the command."

But despite his intestinal illness, Castro remains the head of government as president of Cuba's Council of State. And he let a clear opportunity to relinquish power pass this month by announcing he'll run again for the National Assembly on Jan. 20.

Within weeks after that balloting, the newly formed parliament is expected to select a new Council of State and its president. There has been no official word about Castro's intentions for this process. Cuba's unchallenged leader since 1959, he has held the council presidency since its 1976 creation.

Questions about Castro's immediate future bounced between Miami, Washington and New York after a Cuban state television announcer read Castro's comments about Cuba's leadership.

"My elemental duty is not to cling to positions, or even less to obstruct the path of younger people, but to share experiences and ideas whose modest worth comes from the exceptional era in which I lived," Castro wrote in the last paragraph of a letter about climate change.

But in the next sentence, Castro invoked the example of renowned Brazilian architect Oscar Niemeyer, who is still working at 100, making clear that no matter what title he holds, he will always be busy. "I think like Niemeyer, that you have to be of consequence up to the end," Castro wrote.

The statement was so vague that Castro "left himself room to do anything he wants," said Phil Peters, of the pro-democracy Lexington Institute, a Washington area think tank. "He is sort of hinting, teasing."

Castro already appears to have assumed an advisory role while Raul attends to daily government matters, Peters observed Tuesday in a teleconference of Cuba specialists assembled by the Council of Foreign Affairs in New York.

With no changes in U.S.-Cuba relations expected during the 2008 American presidential campaign, Castro could opt to remain as council president as long as President Bush is in office, in an effort to avoid appearing weak while his nemesis talks tough on Cuba.

The post-Castro era can't come soon enough for the Bush administration, which used Castro's essay as an opportunity for more sharp comments.

White House press secretary Dana Perino said it is "hard to make out what he is saying, or what he means," but insisted that democracy would "soon" come to the island. And State Department spokesman Tom Casey mocked the letter, saying: "Listening to Fidel talk about what will happen after him is like the old country song: 'How can we miss you, if you never leave?"'