But there’s nothing like a diplomatic crisis to focus a head of state’s mind, and his nearly two-hour rant against the presidents of Mexico and Uruguay on Monday evening showed off the old Castro in vintage form.

The region’s only communist ruler was apoplectic over a United Nations resolution-introduced by Uruguay and supported by Mexico and several other Latin American governments-condemning Cuba’s totalitarian regime.

Castro accused Mexico’s Vicente Fox of urging him to leave a U.N.-sponsored conference on poverty held in the Mexican city of Monterrey last month prior to the scheduled arrival of U.S. President George W. Bush. To prove his point, Castro took the unprecedented step of playing a recording of the 18-minute phone conversation he had with Fox two days before the poverty conference got underway on March 21. The recording showed the Mexican president pleading with his Cuban counterpart to rush back to Havana within hours of the conference’s opening.

But Castro’s real bone of contention was Mexico’s unprecedented decision to back the anti-Cuba resolution, which passed the U.N. Human Rights Commission by a two-vote margin last week. Speaking live on both of Cuba’s state-run television channels, Castro said Fox had promised in early February-during a brief visit to the island nation-that Mexico would not support any U.N. resolution criticizing Havana’s appalling human-rights record. “They all lied left and right,” roared Castro, referring to Fox and fellow rancher Bush. “The pledge of not supporting, promoting or supporting a resolution against Cuba was despicably betrayed.”

And in a memorable outburst of venom, the Cuban president derided Uruguayan President Jorge Batlle as “a hungover, abject Judas”-a characterization that prompted Montevideo to sever diplomatic ties with Havana on Wednesday and give the Cuban ambassador 72 hours to pack his bags. El Salvador’s Francisco Flores joined the fray later that day, blasting Castro for releasing the tape of a private conversation between two heads of state.

Strangely enough, the deepening diplomatic isolation of Cuba among its Latin American brethren comes at a time when relations with Castro’s longtime nemesis to the north are warming up on a number of levels. A veritable cavalcade of American senators, congressmen, CEOs and celebrities has swung through Havana since the start of the year to shake hands with the aging Cuban leader and discuss prospects for lifting the 41-year-old U.S. trade embargo. A delegation led by U.S. Sen. Barbara Boxer of California that traveled to Cuba earlier this month included the likes of Grateful Dead drummer Mickey Hart and British-born starlet Julia Ormond-and, on an earlier visit, ’70s-era singer-songwriter Carole King serenaded Castro with a fawning rendition of her signature tune, “You’ve Got a Friend.” Archer Daniels Midland and other U.S. agribusiness corporations have racked up an estimated $73 million in food sales since last fall, and a new precedent will be set next month when former U.S. president Jimmy Carter kicks off a six-day visit on May 12.

The Carter visit could be a win-win situation for both Castro and the expanding ranks of Cuban dissidents. The Cuban president extended the invitation when he bumped into Carter at the funeral of the former Canadian prime minister Pierre Trudeau in October 2000. When the Georgia native took him up on the idea, Castro made a point of saying that Carter-who will become the first U.S. ex-president to set foot on Cuban soil during the Castro era-could venture anywhere and voice any criticisms during his stay in the country. In the light of his longtime championing of human-rights causes, Carter is expected to meet with anti-Castro politicians, independent journalists and librarians, trade unionists and other prominent members of the regime’s growing opposition.

Organized dissent was practically nonexistent in Cuba 10 years ago. That has changed dramatically in the past three years, and major players in the political opposition recently joined forces to collect 10,000 certified signatures on a petition calling for a national referendum on communist rule. Known as the Varela Project, its leading organizers plan to formally submit those signatures to the rubber-stamp National Assembly next summer. Their campaign is expected to be a significant topic of interest for Carter. More than 90 percent of Cuba’s 150 dissident organizations have thrown their support behind the referendum drive, and most of them welcome the chance to meet the outspoken human-rights advocate on their home turf. “It’s quite positive because he will surely make contact with us,” says Hector Palacios, a senior official of the broad-based Todos Unidos (Everyone United) coalition of opposition groups. “Anything that has to do with opening up the country is good.”

That has long been the objective of successive administrations in Washington. As the trade embargo against Castro continues to erode, the pressure to rescind it altogether will mount. Republican senators like North Dakota’s Byron Dorgan have introduced legislation that would repeal laws preventing most private U.S. citizens from visiting Cuba as tourists. Other legislators from farming states like Nebraska and Mississippi have sponsored similar proposals that would loosen up restrictions on exporting grains and other food products to the country.

But the big question remains unanswered: who will go first, Fidel or the trade restrictions? If it’s the latter, some hard-line dissidents argue that a resumption of trade with the United States will only shore up a regime that, they say, has lost the support of a vast majority of the 11 million citizens who remain in Cuba. “The lifting of the embargo is going to happen,” says Martha Beatriz Roque, the director of the Havana-based Cuban Institute of Independent Economists. “What I don’t want to see is that its removal winds up consolidating the power of this government. Because a political opening will never occur as long as Fidel is still in power.” Given Castro’s renewed burst of energy and rage this week, it may be prudent to bet on the Cuban leader outlasting the embargo.