Former US President Jimmy Carter aimed to hit all the right points on a three-day trip to Cuba. He sat with revolutionary icon Fidel Castro and his brother Raúl, and met today with leading Cuban dissidents, calling attention to the human rights and political issues that have long been at the center of stalled US-Cuba relations.

But Mr. Carter was unable to resolve a key sticking point between the Castro regime and Obama administration: the release of jailed US contractor Alan P. Gross.

While that, in itself, was enough to cast Carter's trip as a disappointment, analysts say Mr. Gross's release would not likely have provided the impetus for a major turning point in relations that were severed 50 years ago.

IN PHOTOS: Cuba's underground economy

“Even if Carter had returned with Alan Gross, I don’t think it would have caused a fundamental shift in relations between the countries,” says Jana Lipman, a professor at Tulane University who has studied relations between the countries. “The status quo has been a strong barrier to the improvement of relations between the US and Cuba for a long time."

Arrested in December 2009 while working on a US government project, Gross received a 15-year prison sentence earlier this month for bringing satellite communications equipment to Jewish groups in Cuba, which the government called espionage.

US-Cuba ties hits snag

Carter met with Gross before leaving the Caribbean island on Wednesday, yet even ahead of the meeting he sought to dampen expectations for his release. "I am not here to take him out of the country," Carter told reporters Tuesday, amid speculation that he might repeat his successful negotiation in North Korea for the release of American teacher Aijalon Gomes.

The Obama administration has stated that Gross’s release is necessary before the countries can work on improving relations.

“It’s clear that the Obama administration wants to engage with Cuba. It’s their preferred course of action,” says Jose Azel, a Cuban exile and senior scholar at the University of Miami’s Institute for Cuban and Cuban-American Studies.

In 2009, President Obama lifted some restrictions on travel and the sending of remittances to Cuba, in what his press secretary called measures intended “to reach out to the Cuban people.”

Gross’s arrest and subsequent conviction “halted” any further negotiations, Professor Azel says. “What Cuba wants and needs is US tourists and their money,” he says. “And the only thing Castro has to offer the US in exchange at this point is the release of Gross.”

Still, Carter’s visit could open the door for negotiations that lead to Gross’ release. The Cuban state-controlled media reported Wednesday that President Raúl Castro remained open to discussing any topic with the US government.

Carter meets bloggers, rights advocates

Raúl, who assumed the presidency from his ailing older brother in 2008, invited Castro to the island to learn about some of the country’s new economic policies and to discuss ways to improve relations between the two countries.

Carter met with Havana’s Catholic archbishop, dissident bloggers, human rights advocates, members of leading opposition group Ladies in White, and some of the recently released Group of 75 political prisoners, who were jailed in 2003 during the “Black Spring” crackdown.

Carter told them he “wanted to express his solidarity and his recognition of the movement for civil rights and also the emerging civil society,” said human rights leader Elizardo Sanchez, according to the Associated Press.

It was his second visit to the island and he remains the only US president, current or former, to visit Cuba since Fidel Castro’s 1959 revolution. “I hope we can contribute to better relations between the two countries,” Carter said today during a press conference, calling for the US to end its trade embargo and for Cuba to allow more freedoms to its people.

For Cuban dissident blogger Yoani Sanchez, Carter’s visit provided a bit of hope for the future.

Ms. Sanchez – who last year won a prestigious journalism award from Columbia University but was barred by the Cuban government from attending the awards ceremony – met with Carter this morning.

She said she could not discuss the content of the meeting, but she later tweeted, “Life goes on; Today is not the end of anything but I wish it was the beginning.”

IN PHOTOS: Cuba's underground economy