Venezuela's President Nicolas Maduro speaks during a meeting with governors and ministers at Miraflores Palace in Caracas in this handout photo provided by Miraflores Palace December 22, 2014. (Handout/Reuters)

A LOT of people were caught off guard by the sudden announcement of rapprochement in U.S.-Cuban relations this month, but probably none more so than Venezuelan President Nicolás Maduro. Mr. Maduro’s regime is a de facto satellite of Havana: Thousands of Cuban operatives are seeded in its security services and, in a deal that has long propped up the Castro regime, Venezuela supplies Cuba with 100,000 barrels of oil a day in exchange for the services of a few thousand doctors.

Yet Venezuelan observers believe Mr. Maduro was blindsided by the accord between President Obama and Raúl Castro, which was negotiated in secret. At a minimum, Venezuela was excluded. The day after the announcement, Mr. Obama signed legislation imposing new sanctions on Venezuelan officials for violations of human rights. Meanwhile, numerous commentators pointed out that for Cuba, a chief motive for the opening to the United States is to lessen its dependence on Caracas.

Mr. Maduro, who had staged an anti-American rally just two days before the announcement, tried to put a good face on his embarrassment, saying, “We have to recognize the gesture of President Barack Obama, a brave gesture and historically necessary.” But a day later he was tweeting his frustration: “On the one hand, [Mr. Obama] recognizes the failure of the policy of aggression and embargo” against Cuba, “and on the other hand, he starts the escalation of a new stage of aggression” against Venezuela.

While we don’t support the way Mr. Obama has gone about relaxing sanctions against Cuba, there is reason for his discrimination between the two countries. Repression in Venezuela has steadily escalated this year: More than 40 people were killed when security forces cracked down against opposition street protests, and bogus criminal cases have been brought against senior opposition leaders. One, Leopoldo López, has been imprisoned since February.

As Venezuela’s economic crisis — which led to severe shortages and high inflation even before the collapse in the price of oil — steadily escalates, Mr. Maduro’s reaction has been the opposite of Mr. Castro’s. Rather than seeking to improve relations with the country most able to supply fresh investment, the Venezuelan ruler has expelled U.S. diplomats and escalated anti-American rhetoric. Most recently, state prosecutors charged, ludicrously, that opposition leader María Corina Machado and the U.S. ambassador to Colombia were part of a conspiracy to assassinate Mr. Maduro.

It will be no surprise if Mr. Maduro, racing after his tutors in Havana, now seeks to strike his own truce with Washington. In that case, however, the White House should not repeat the mistake of bailing out a failing regime without receiving meaningful concessions on democracy and human rights. An essential condition for improved U.S.-Venezuelan relations should be the release of Mr. Lopez and all other political prisoners, as well as the dropping of the absurd case against Ms. Machado. In addition, Mr. Maduro should be required to restore freedom of the press — and stop blocking the provision of newsprint to opposition newspapers — as well as tolerate peaceful opposition demonstrations.

Whether or not Mr. Maduro wants better relations, the United States should be joining with the Vatican, Brazil and other Latin American nations to press the Venezuelan regime to resume negotiations with the opposition. The country desperately needs a domestic accord that will allow it to confront its economic crisis and rapidly deteriorating social conditions. Absent such a grand bargain, nothing can save Mr. Maduro — and Venezuela — from disaster.