HAVANA — Raúl Castro, who took over from his brother Fidel 12 years ago and led Cuba through some of its biggest changes in decades, is expected to step down on Thursday and hand power to someone outside the Castro dynasty for the first time since the Cuban revolution more than half a century ago.
During his two terms as president, Mr. Castro, 86, opened up his Communist country to a small but vital private sector and, perhaps most significantly, diplomatic relations with the United States. It was a notable departure from his brother’s agenda, yet it was possible only because he, too, was a Castro.
His handpicked successor, Miguel Díaz-Canel Bermúdez, 57, is a Communist Party loyalist who was born a year after Fidel Castro claimed power in Cuba. His rise ushers in a new generation of Cubans whose only firsthand experience with the revolution has been its aftermath — the early era of plenty, the periods of economic privation after the demise of the Soviet Union, and the fleeting détente in recent years with the United States, its Cold War foe.
Officials started gathering here in Havana on Wednesday morning and put forward Mr. Díaz-Canel as the sole candidate to replace Mr. Castro, all but assuring his selection by the Communist Party.
Though Mr. Díaz-Canel’s path to the top office has been forecast for years, many an heir apparent before him has fallen by the wayside in the search for a successor to lead the country, whether because of party disloyalty, snide remarks or projecting too much power for the Castros’ liking.
In that delicate balancing act, Mr. Díaz-Canel, a former provincial leader who became the most important of Cuba’s vice presidents, has shown the sort of restraint prized by the Castros. But that same caution has left him an enigma both inside and outside the country.
Few American officials — even those in the United States Embassy in Havana — have spent time with him or can claim to have shared more than a few passing words. Even the most seasoned Cuba experts have only faint clues as to what he will do, how he will lead and how much latitude he will have to chart his own course.
Cuba’s next president could be hemmed in from multiple sides. For one, Raúl Castro is expected to remain the head of the Communist Party and wield great influence. Even Fidel, who ruled Cuba since the revolution, did not officially become president until years later, allowing others to occupy the post while he ran the country.
Beyond that, the diplomatic opening with the United States has closed abruptly under President Trump, limiting Mr. Díaz-Canel’s ability to maneuver economically.
“There is nothing in his résumé to suggest he is going to take risks,” Theodore Piccone, a Cuba scholar at the Brookings Institution, said of Mr. Díaz-Canel. “But that is the way the system works — anyone willing to take the risk before now would not be in line to be the president.”
Mr. Castro is leaving office at a time of tremendous change on the island, both real and promised.
In just the last decade, Cuba has lost its defining leader, Fidel, which made way for Raúl to take unprecedented steps to loosen the state’s grip on the economy and begin to nurture a private sector.
Then, two years ago, the nation brokered a détente with the United States, paving the way for the reopening of the American Embassy and the first visit of a sitting United States president in 88 years.
But change is often a managed affair in Cuba, orchestrated to maintain order while leaving little to chance or, especially, political uncertainty. While historic, the economic changes in Cuba have been halting, to the frustration of many Cubans hoping for better pay and more opportunity. So, too, has foreign investment, with leaders leery that it could grow to the point that they can no longer control it.
Now, the country’s next president will face a new set of challenges. Since coming to office, Mr. Trump has lashed out at Cuba and reversed, in spirit if not entirely in deed, the new relationship that President Barack Obama established with the Cuban government.
As Cuba seeks to modernize its moribund economy with a new generation of leaders less tethered to the past, the United States appears to be moving back toward a policy of isolation. Fewer American tourists are visiting Cuba and bringing dollars with them, in no small part because of Mr. Trump’s decision to undo some of Mr. Obama’s easing of restrictions on travel to the island.
And then there are the mysterious ailments that affected a group of American diplomats stationed in Havana. American officials say they were attacked by unidentified devices that damaged their hearing. In response, the United States issued a travel warning to its citizens and reduced the size of its embassy staff by two-thirds. For now, there is no office in Cuba that can issue visas for Cubans seeking to visit family members in the United States.
How the sudden slide in relations with the United States will affect Mr. Díaz-Canel’s ability to sustain the economy and stave off domestic pressure remains unclear.
Mr. Díaz-Canel, though a prominent advocate of bringing internet service to the island and considered a relatively modern thinker within the context of Cuba, is not expected to deviate from the party line or the prescribed, deliberate path toward economic reform outlined by his predecessor.
In all likelihood, he will govern with less flexibility than Mr. Castro, who enjoyed a special status on the island because of his family name and revolutionary credentials. And Mr. Castro is not vanishing from the scene. As president of the Communist Party, he will preside over an important bastion of power.
“Díaz-Canel is one of those people who has risen through the ranks because he represents the prevailing view within the party, not because he himself has taken any particular initiative,” said Benjamin Rhodes, who was a top aide to Mr. Obama and one of the main brokers of renewed relations with Cuba. “I think he is going to be significantly more constrained than either Fidel or Raúl.”
Still, as the public face of this long-awaited transition, Mr. Díaz-Canel has been thrust between the crosscurrents of change and tradition. It will certainly not be an easy task: preserving the achievements of the revolution — socialized medicine and education, among them — amid economic turbulence that threatens the nation’s future.
Mr. Díaz-Canel’s leadership will be defined in some respects by how he manages the competing forces within the country and his own government. Today, the streets of Cuba brim with young people anxious for a new dynamic, one in which the future is valued more than the past and individual prosperity is not considered a threat to historic ideals.
But the ranks of government remain filled by an older, powerful generation of leaders clinging to the past, a group venerated for its connection to the revolution. Their resistance made reform difficult for even Raúl Castro to push through.
Without the same legacy to rely on, Mr. Díaz-Canel will be forced into a minefield of tasks that even his predecessor failed to complete. Chief among them are economic reforms central to the nation’s survival.
He will have to foster the growing private sector, the future engine of the economy and the fulcrum on which employment will hinge, while guarding against the income inequality it often brings.
After years of visible growth, with restaurants and bars popping up across Havana and elsewhere, the government decided last year to stop issuing licenses for private businesses, fearful that the pace was getting out of control.
Some establishments were practically minting money, with hourslong waits for meals that cost as much as a night out in New York. In a nation where government salaries hover around $ 30 a month, this raised concerns not only about inequality, but also the potential for a class of businesspeople with the resources to be politically powerful.
Foreign investment to update Cuba’s crumbling infrastructure is another priority. Business zones launched with much fanfare by the government carry few prospects. The government’s conditions for foreign investment remain unattractive, experts say.
Even the very basics — food and energy — need attention. Cuba imports the majority of its agricultural products, as well as its oil. Inefficiencies and failing infrastructure have left a poor farming legacy that keeps food off the tables of many regular Cubans.
The slow collapse of Venezuela, a longtime benefactor of Cuba, has expedited the crisis and robbed the country of much-needed resources. Venezuela has already cut its oil shipments to Cuba drastically, worsening the island’s finances.
Perhaps most immediately, Mr. Díaz-Canel will have to unify two separate currencies in widespread use on the island, a gambit that will produce big winners and losers in a country that prides itself on equality.
“It’s a high-wire act,” said Julia Sweig, a Cuba expert at the Lyndon B. Johnson School of Public Affairs at the University of Texas at Austin. “The expectation dynamic among the Cubans is that they still want a functioning state that delivers services. And yet they also want the state to get out of the way.”
To say that Cuba has remained in stasis would be unfair. Beginning with a slate of economic reforms pushed forward by Raúl Castro, all the way through to the decision to restore diplomatic relations with the United States, the nation has been opening.
Many have criticized the pace at which economic reforms are rolled out, but the delay is due in part to the magnitude of the experiment the nation is conducting: an effort to define its own brand of socialism in a modern world.
The Cubans have sought counsel from the Chinese and, most recently, the Vietnamese, whose leadership was in Havana last month for high-level talks. But the Cuban government is also deeply worried about liberalizing too quickly and converting its fragile gains into a sideshow for tourists plowing into the next big Caribbean destination.
Move too slowly and it risks economic collapse and widespread discontent, especially from a young population that has known only hard times. Move too fast, and it risks unstitching the unique tapestry of Cuba’s social project.
To drive home this point, Raúl Castro for years has shown young officials a documentary about the oligarch class in Russia after the demise of the Soviet Union. In Cuba, the screenings offer a cautionary tale of how a nation and its values can unravel if economic transition is not managed carefully.
“Raúl Castro is a conservative if the regime’s future and the future of the achievements of the revolution are in danger,” said Hal Klepak, a military analyst and biographer of Raúl Castro. “He’s a reformist in every other occasion.”
That is the sort of continuity that many are expecting from Mr. Díaz-Canel — especially with Raúl Castro still in the picture as party president.
“I think he is very smart, very cautious, as I think he better be for a while, until he delivers some goods,” Mr. Klepak added about Mr. Díaz-Canel. “I view him as a reformist with Raúlista credentials: He’s reformist while reform reinforces the achievements of the revolution.”
“The moment that reformism threatens the achievements of the revolution, he flips,” he added.