“I hope we can contribute to better relations between the two countries,” said Jimmy Carter in describing his mission to Cuba at the end of March. During a remarkable three-day trip, the thirty-ninth president of the United States assumed the multifaceted role of intermediary, diplomat, conciliator and highest-profile proponent of a more positive future in Washington’s approach to Havana.

Since he made history by visiting Cuba nine years ago, Carter has remained the only former US president to go to Havana after the 1959 revolution. His second visit was a meticulously organized affair. At the top of his agenda: establish a relationship of confidence with Cuban President Raúl Castro; listen carefully to Cuba’s grievances; convey US interests in advancing human rights and democracy; and press for the release of imprisoned US Agency for International Development (USAID) subcontractor Alan Gross, whose case has become a major impediment to improved ties.

In less than seventy-two hours, Carter managed to meet with almost every key constituency that could provide information, credibility and political cover to advance his effort to change US policy: recently released political prisoners, the head of Cuba’s Catholic Church, Cuba’s leading human rights advocates and dissidents, the staff of the US Interest Section as well as ambassadors whose countries have full relations with Cuba, and leading Cuban economic, political and foreign policy officials. Carter also visited Gross, convicted in March and sentenced to fifteen years for crimes against the Cuban state for surreptitiously distributing satellite communications equipment to religious groups under a USAID “democracy” promotion program. And, in a significant gesture to the Castro government’s effort to obtain freedom for the so-called “Cuban Five”—counterterrorism agents arrested in Florida by the FBI for conspiracy to commit espionage (they were monitoring violent exile groups) and incarcerated for more than twelve years in the United States—Carter met with their mothers and wives during his brief stay in Havana.

Carter described his meeting with retired comandante in chief Fidel Castro as a visit of “old friends.” But his six-hour summit with President Raúl Castro on March 29—which included dinner at one of Havana’s leading restaurants—was the focus of his trip. Raúl gave Carter “an overview of the Cuban revolution”—including the 1961 Bay of Pigs invasion, Cuba’s uneasy relationship with the Soviet Union, Cuba’s involvement in Angola, his relationship with Fidel—and briefed him on the speech the Cuban president plans to make at the Communist Party Congress, scheduled for the fiftieth anniversary of the US invasion and of Fidel’s announcement, on April 16, 1961, that Cuba was a socialist state. The two also discussed “confidential issues,” Carter told the press before he returned to the United States, which he would share privately with President Obama.

Although Carter’s parting press conference received very little coverage in the mainstream media, it was a tour de force—the most forceful and honest series of statements on US policy and Cuba ever made by an ex-president or any other American dignitary. In his opening statement Carter characterized the US trade embargo as “a serious mistake that my government continues to make” and called for sanctions to be lifted “immediately.” While pressing for greater freedoms for the Cuban people, Carter also noted that US citizens, with a few exceptions, were denied the freedom to visit Cuba. He criticized as counterproductive the 1996 Helms-Burton Act, as well as unnamed Cuban-American members of Congress, for “punishing the Cuban people” with restrictions on aid, trade and travel to Cuba.

Among the immediate steps President Obama could take to improve relations, Carter said, would be to take Cuba off the terrorism list. Cuba’s inclusion, which mandates severe restrictions on financial credits, is “completely unfounded,” he explained, and he revealed that US and Cuban intelligence have actually cooperated in counterterrorism efforts against Al Qaeda.

In perhaps his boldest—and riskiest—statement, Carter issued a call for the US government to release the Cuban Five. At the same time, Carter called on the Cuban government to free Gross “because he is innocent of any serious threat to the Cuban people.” Gross’s conviction could be overturned by Cuba’s Supreme Court on appeal, Carter suggested. Raúl Castro should pardon him, or release him to his family on humanitarian grounds.

When a reporter asked Carter if he would be willing to act as a mediator between Havana and Washington, he said that if both countries solicited his support, “I would be pleased to help, but I believe that that is extremely unlikely.” The Cubans seemed ready to use him in that capacity. Seeing Carter off at the airport, Raúl Castro said he was sending a message back to Washington: Cuba was ready to talk with the United States about differences and common interests, but as an equal and without conditions.

How that message, and President Obama’s debriefing of Carter, will be received remains to be seen. The Cuban refusal to use the opportunity of the former president’s visit to release Alan Gross weakens Carter’s argument to Obama that the time is right to make substantive reforms in US policy. Since Obama relaxed restrictions on US citizens’ travel to Cuba in January—in effect returning the travel policy to the more liberal Clinton era—the administration has taken no further steps to improve relations. In a major speech in Santiago, Chile, on March 21, Obama committed himself to “try to break out of this history that’s now lasted longer than I’ve been alive.” But he appeared to set a condition for any further changes: the Castro government “must take some meaningful actions to respect the basic rights of their own people.” The United States, he stated, would “continue to seek ways to increase the independence of the Cuban people.” Indeed, while Carter was in Cuba, the State Department submitted USAID’s $20 million Cuba “democracy” program to Congress—the very one that financed Gross’s semicovert operation to distribute satellite communications gear. “Obama doesn’t have a foreign policy toward Cuba,” says Julia Sweig, who heads the Latin American studies program at the Council on Foreign Relations. “His administration’s Latin America team is playing defense—protecting their standing with the Congress and otherwise wagering that doing the right thing on Cuba never advances government careers.”

Nevertheless, at 86 Carter remains committed to using his unique stature to pursue a goal that dates to the beginning of his presidency. Shortly after his inauguration he issued a secret directive on changing Cuba policy. “I have concluded that we should attempt to achieve normalization of our relations with Cuba,” it stated. His administration opened the channels of diplomacy and free travel, but it never achieved the full rapprochement Carter envisioned. “My dream is to see this issue resolved before I die,” Carter told his Cuban hosts during a private meeting in Havana. “I don’t know if that will happen.”