In 1993, amid a Cuban economic crisis sparked by the collapse of the Soviet Union, American intelligence officials estimated that there was “a better than even chance that Fidel Castro’s government will fall within the next few years.” Such an outcome still seemed possible in August 1994, when riots erupted near the Havana waterfront. To quell the turmoil, Fidel unleashed a flotilla of balseros (rafters), causing heartburn for the Coast Guard and spooking the Clinton administration, which ultimately got Cuba to curb the tsunami of refugees in exchange for a bilateral accord that obliged the U.S. to accept no fewer than 20,000 Cuban migrants each year. This policy has allowed the Castro brothers to export many of their critics and democratic opponents. Meanwhile, the regime’s finances have been propped up by foreign tourism, overseas remittances, Chinese investment, and (since the rise of Hugo Chávez) Venezuelan oil largesse.

Over the past half century, the Communist government has reached many potential “turning points,” only to keep moving straight ahead. Now it has arrived at another. Writing in Newsweek, former Mexican foreign minister Jorge Castañeda lists three factors that could amount to “a perfect storm.” First, Cuba is being ravaged by its worst economic catastrophe since the post-Soviet implosion, marked by electricity blackouts, food shortages, and a mushrooming external-debt burden. Second, public unrest on the island is growing — and attracting significant global attention. Third, an ailing Fidel “has ceded day-to-day control to his brother Raúl,” who does not possess the political instincts of El Jefe.

The regime shows no signs of crumbling anytime soon, but these circumstances pose a major challenge to Cuban stability. Recent incidents have thrown the floodlights on Cuban repression, and the dictatorship is now facing greater international opprobrium than at any moment in its 51-year existence.

Consider the bracing statement issued on November 30 by several dozen prominent black Americans, including Princeton scholar Cornel West, the Rev. Jeremiah Wright, and former Black Panther Kathleen Cleaver (ex-wife of the late Eldridge Cleaver). Titled “Acting on Our Conscience,” it demanded the liberation of Darsi Ferrer — an Afro-Cuban political prisoner who was staging a hunger strike — and condemned the “increased violations of civil and human rights for those black activists in Cuba who dare raise their voices against the island’s racial system.” Given Fidel’s longtime romance with black progressives, these remarks must have dismayed the 83-year-old tyrant — who, lest we forget, created a white-dominated power structure to rule a country that has been majority-black since the 1960s.

Ferrer isn’t the only jailed Afro-Cuban dissident who recently launched a hunger strike. On February 23, Orlando Zapata died after fasting for twelve weeks to protest abuses at the notorious Kilo 7 prison. Subsequently, police violently disrupted a public demonstration involving Zapata’s mother and the Ladies in White, a group of women who are relatives of Cuban political detainees. In response, Cuban-American pop star Gloria Estefan led an enormous march down Miami’s Calle Ocho to express solidarity with the Ladies. Similar rallies took place in other U.S. cities. On her website, the Colombian singer Shakira called the women “true heroines of our time” and “exemplars of female courage.”

Will the self-starvation of Zapata and the brutal treatment of the Ladies mark a watershed in global attitudes toward Castroism? “There is definitely a new dynamic,” says José Cárdenas, who served as a senior official for Latin America in the Bush administration. He likens the current moment to the period immediately following the 1986 publication of Against All Hope, Cuba’s equivalent of The Gulag Archipelago, by former political prisoner Armando Valladares. “That was a signal event that really changed the international perception of what was going on in Cuba,” says Cárdenas. “The death of Zapata caused people to take a closer look and recognize that the abuses continue unabated.”

To be sure, there are still knee-jerk Castro apologists, and there are still those who hate the U.S. embargo more than they hate the dictatorship. Many Latin American politicians remain hesitant to denounce a regime that, in the popular consciousness, symbolizes resistance to Yanqui imperialism. As Zapata was dying in Cuba, Mexican president Felipe Calderón, a conservative, was cordially welcoming Raúl Castro to the Rio Group summit in Cancún. Brazilian president Lula da Silva — a social democrat and warm friend of Fidel’s who conducted hunger strikes during his own days as a political prisoner but now claims to oppose them in principle — refused to scold Havana for Zapata’s demise, telling the Associated Press that “we have to respect the decisions of the Cuban legal system and the government to arrest people depending on the laws of Cuba, like I want them to respect Brazil.”

But the views of Latin American governments on the whole seem to be shifting, says former CIA Cuba analyst Brian Latell. Take Panama and Chile, both of which now have center-right presidents. Panama’s Ricardo Martinelli has terminated a Venezuelan-financed program that brought Cuban eye doctors to his country, and Chile’s Sebastián Piñera has vowed to do everything he can to promote human rights and democracy in Cuba. Meanwhile, on March 11, the European Parliament passed a resolution deploring Zapata’s “avoidable and cruel” death and urging the release of all Cuban political prisoners. It also expressed alarm about the deteriorating health of another hunger striker, Guillermo Fariñas. As we went to press, Fariñas was still fasting. Should he die, “the ensuing uproar would be deafening,” writes Florida International University professor Marifeli Pérez-Stable.

What does all that mean for U.S. sanctions against Cuba? “This is clearly the wrong time to lift the embargo, because the regime is under pressure — not only internally, but internationally,” says former State Department official Susan Kaufman Purcell, director of the Center for Hemispheric Policy at the University of Miami. Moreover, the Castro government has made a habit of scuttling U.S. efforts to improve bilateral relations. When President Ford sought rapprochement, Cuba dispatched a massive number of military personnel to aid Communist forces in the Angolan civil war. When President Carter established a U.S. mission in Havana, Fidel sent thousands of dangerous criminals and mental patients to Florida as part of the Mariel boatlift. When President Clinton loosened the embargo, Cuban aircraft shot down two planes operated by “Brothers to the Rescue,” a Cuban-American group that assists seaborne refugees.

Similarly, President Obama initially hoped to launch “a new beginning with Cuba.” In a gesture of goodwill, he eased restrictions on family travel and remittances to the island. But Havana once again failed to reciprocate: In December, Cuban security agents arrested Alan Gross, a U.S. Agency for International Development (USAID) contractor seeking to foster civil society on the island. The regime has since been holding him on trumped-up spying charges.

After the Gross detention, USAID-funded trips aimed at nurturing Cuban democracy were temporarily suspended. But on April 9, the Miami Herald reported that the agency had given its partner organizations the green light to resume them. Cuban officials are “really worried” about the USAID programs, says Latell, author of the magisterial 2005 book After Fidel. A 2006 Government Accountability Office study found that those programs are plagued by managerial difficulties and inadequate oversight, but it also noted that Cuban dissidents felt USAID activities “provided moral support and enhanced their ability to continue their pro-democracy work.”

In a statement on March 24, Obama lamented that “Cuban authorities continue to respond to the aspirations of the Cuban people with a clenched fist.” Would scrapping the embargo help spur liberalization? Peter Orr, who served as USAID Cuba coordinator under President Clinton, is doubtful. Foreign investment has been pouring into Cuba since the mid-1990s, as have foreign tourists. Both have strengthened the dictatorship. It is somewhat fanciful to think that still more mojito-sipping sunbathers would catalyze a transformation.

Cuban-American family visitors are a different matter. After President Carter relaxed the travel ban in the late 1970s, a surge of Cuban exiles returned to the island and fomented real instability. Could that happen again? The family visitors of 2010 are, on balance, substantially poorer than those who went back during the Carter years, says Latell, and the legal emigration channels opened by the 1994 migration accord function as a population safety valve. But Orr believes that Cuban-American travel is still a huge asset to the island’s democracy activists. “So, in effect, the Obama administration’s removing restrictions on this travel is the most supportive thing they could have done for the dissident movement in Cuba,” he told me in an e-mail last year.

The broader U.S. embargo should be used as a tool to incentivize Cuban liberalization. Latell reckons that most senior members of the military and Communist bureaucracy — including Raúl Castro — favor Chinese-style economic reforms, though they do not necessarily want Cuba to become what China is today. But Fidel rejects the Deng Xiaoping model, and any large-scale implementation of that model presupposes his death. Latell suspects that if Fidel died and Raúl (who turns 79 on June 3) were still in control as president, Havana would adopt a more pragmatic approach to the United States, and might even be willing to free political prisoners in return for U.S. investment.

If America ditched sanctions tomorrow without first obtaining serious concessions, it would be rewarding the Cuban government at a time when that government appears increasingly vulnerable. The embargo may seem a hopeless anachronism. But it could prove a valuable bargaining chip, and it’s worth keeping at least a little while longer.