The Bush administration remains hopeful that the death of ailing Fidel Castro would unleash grassroots pressure among Cubans for democratic change.
But many analysts see little threat to the regime under the thus-far seamless succession of brother Raul.
As United States officials see it, the seismic political event for Cuba has yet to come.
"We don't feel that we've lost an important moment, because quite frankly, we don't see any significant possibility of change of any kind until Fidel is gone," Tom Shannon, the top State Department aide for Latin America, says.
Intestinal surgery last July led to the transfer of power from Fidel, 80, to Raul, 75.
US intelligence agencies do not expect the elder Castro to live long but his two brothers, Raul and Ramon, insist he is recovering.
US presidents have been waiting for decades for Fidel to die and to take his communist project to his grave.
President George W Bush, who has especially close ties to the anti-Castro Cuban-American community, has tried to hasten a democratic transition by tightening the embargo against the island.
But many observers say the post-Fidel era has begun with Raul Castro clearly in control.
Lt Gen Michael Maples, head of the Defence Intelligence Agency, said last month that Raul Castro has the "widespread respect and support" of military commanders, whose backing he believes will be crucial in the succession process.
He said Raul Castro should be able to fend off any move to depose him "at least for the short term."
Brian Latell, a former top Cuba analyst at the CIA, agrees and says Raul Castro has been acting more boldly than expected, encouraging debate among Cubans and calling on university students to "fearlessly" discuss the country's problems. There is little evidence of pro-democracy ferment in Cuba.
The answer to whether that reflects fear or contentment on the island depends on whom one asks.
One visible indication of unrest is the single word that appears on occasional street signs: "Cambio" ("Change").
US Congressman Lincoln Diaz-Balart, a Cuban-born Florida Republican, says the calm under Raul is illusory.
"The regime of Fidel Castro is not viable without Fidel Castro," he says.
"A transition to democracy in Cuba is inevitable, but Fidel Castro needs to die for the future of Cuba to begin."