President Obama touched down in Cuba on Sunday, becoming the first American leader to visit in nearly nine decades. His trip, the result of a stunning policy reversal 15 months ago, holds the potential to forge closer ties between longtime adversaries and exorcise one of the last ghosts of the Cold War.
Just hours before Air Force One arrived at José Martí International Airport, however, the challenges of working more closely with Cuba became apparent as police officers, surrounded by pro-government demonstrators, detained dozens of protesters at a weekly march of the Ladies in White, a prominent dissident group.
The protest, which occurs on most Sundays outside a church in the Miramar district of Havana, was widely expected to be a test of Cuba’s tolerance for dissent during Mr. Obama’s trip. The arrests confirmed that the government was maintaining and intensifying its repressive tactics ahead of the visit.
“We thought there would be a truce, but it wasn’t to be,” said Elizardo Sánchez, who runs the Cuban Commission on Human Rights and National Reconciliation, noting that the arrests took place “in the moment that Obama was flying in the air to Cuba.”
The question of how to handle political opposition to President Raùl Castro’s government is one of many political thickets that Mr. Obama will have to navigate here.
Berta Soler, the head of the Ladies in White, is one of a dozen dissidents invited to meet with Mr. Obama on Tuesday at the United States Embassy. Other dissidents said, however, that it was not clear if she would attend because of her opposition to the American president’s policy of engagement.
Mr. Obama also arrives with a great deal of support for his effort to bring old enemies together, both among the Cuban people, who describe Mr. Obama as a transformative figure, and within the United States, where interest in Cuba has already begun to swell.
The president, who arrived with the first lady, Michelle Obama; their daughters, Sasha and Malia; and his mother-in-law, Marian Robinson, will begin and end his trip as a tourist in chief. He planned to stroll through Old Havana on Sunday and attend an exhibition baseball game between an American major-league team and Cuban players on Tuesday.
In between, his itinerary is shaped by the contradictions that still complicate the United States’ relationship with Cuba: a meeting on Monday with Mr. Castro at the Palace of the Revolution, the seat of the Communist government, and another on Tuesday with the group of dissidents who have been victims of government repression.
Mr. Obama was accompanied by a large delegation of members of Congress from both parties who are eager to support his call to lift the trade embargo against Cuba, which still looms as an obstacle to the rapprochement the president is seeking.
Also along for the journey were dozens of American business executives seeking lucrative opportunities on the island.
As rain began to fall at 4 p.m. on Sunday, the streets of Havana seemed oddly quiet. Just a few cars filled the main thoroughfares. In Old Havana and near the United States Embassy on the Malecón seafront boulevard on Havana Bay, tourists seemed to be the only ones interested in a stroll.
After he arrives, Mr. Obama is scheduled to visit the embassy, where the American flag was raised in August for the first time since President Dwight D. Eisenhower severed diplomatic ties with Cuba in 1961.
Mr. Obama also planned to meet on Sunday evening with Cardinal Jaime Ortega, who played a pivotal role in the secret talks that led to an initial rapprochement in 2014. The cardinal made a clandestine trip to the White House as an interlocutor for Pope Francis to prod an agreement between Mr. Obama and Mr. Castro.
In the Cathedral of the Virgin Mary of the Immaculate Conception, where Mr. Obama was expected to stop on his afternoon tour, Cubans celebrated Palm Sunday while whispering about the American leader’s visit between prayers.
Outside the church, some parishioners sounded surprised when told that the president would be engaging not just with the government, but also with the Roman Catholic Church.
“It’s important for him to understand the church, too,” said Hortencia Dominguez, 58, who appeared for Mass wearing American flag tights. “It’s good for him to come.”
Cubans have shown a great affinity for Mr. Obama throughout his presidency, but their sense of kinship intensified after he announced restored relations with Cuba on Dec. 17, 2014. That date is now recited often as a new starting point for the country, joining other historic dates, like July 26, 1953, when Fidel Castro mounted an attack on the Moncada barracks, initiating a revolution.
Officials have been working for weeks to beautify Havana. Roads with more potholes than flat patches have been repaved. Buildings along the president’s route have also been painted in attractive pastels, prompting Cubans to call the president “St. Obama” and to joke, “Too bad Obama can’t stay for a month or a year.”
The government had also made clear to all Cubans, through editorials, preventive detentions and other means, that it would not toleratedemonstrations or any other form of public dissent — against the government or the United States.
“Respect” is the choice word, the defining principle — a sharp contrast with “imperialism,” the term associated with the United States for more than 50 years.
Still, there are nagging doubts, especially among the young, that anything will change. Outside the baseball stadium that the president will visit on Tuesday, Juliet Garcia Gonzalez, 17, said she was glad Mr. Obama was visiting because he had given her generation hope, a rare commodity in a country that has long seemed stuck in place.