This week’s Summit of the Americas, which opens on Saturday in Cartagena, Colombia, may well be Venezuelan President Hugo Chavez’s last. Right now, though, there’s no guarantee that whoever, or whatever, succeeds Chavez will necessarily bring a change for the better.

Chavez, who faces elections in October, has just left Venezuela for another round of radiation therapy in Cuba to treat a mystery cancer first disclosed last June. It’s uncertain if he will be healthy enough to campaign, or how long he will live if he is re-elected.

His political opposition has united around Henrique Capriles Radonski, the 39-year-old governor of Miranda state who won a resounding primary victory in February. Capriles has pledged to continue many of Chavez’s pro-poor programs, while abandoning the economic policies and expropriations that have hurt economic growth. He also promises to rethink the unsavory associations with Cuba, Syria and Iran that have turned Venezuela into a benefactor of political oppression and terrorism. We see much to admire in Capriles’s progressive, market-friendly and less demagogic approach.

But even if Capriles were to defy the odds and beat the still-popular Chavez, his inauguration is not a given. Chavez’s brother Adan, the governor of the Chavezes’ home state of Barinas, has spoken darkly of the need for “armed struggle” to keep the current government in power. Defense Minister Henry Rangel Silva has said the military would not recognize an opposition victory in 2012. Key members of Chavez’s administration have much to lose, including Rangel and others whom the U.S. Treasury Department has sanctioned for supporting the Revolutionary Armed Forces of Colombia, designated as a narco-terrorist organization. So do countries such as Cuba (which gets two-thirds of its oil and roughly $5 billion a year for providing Chavez with everything from sports trainers to security personnel), Syria (which has received fuel shipments), and China (the beneficiary of a growing range of commercial agreements).

Sharp divisions exist not just between Chavez supporters and the opposition, but within Chavez’s own camp, with would-be successors already elbowing for position. High inflation, rampant crime and shortages of basic foodstuffs and goods have fed unrest -- in fact, Venezuela tops Bloomberg’s most recent listing of countries by their “misery rate.” Throw in the civil militias created and armed by Chavez, with numbers in the tens of thousands, and you have the makings of a potential bloodbath if the election doesn’t go smoothly.

Venezuela’s electoral council has said it would invite monitors to supervise October’s voting, and we hope the Organization of American States and other outside groups will be included. But an election is just a moment. Chavez’s genius has been to deploy the power of the state to intimidate on a day-to-day basis -- as in his use of state media to constantly demean his opponent, and his recent threats to seize banks and companies that finance “the opposition’s destabilizing plans.”

The challenge is to shine a constant light on such oppression. Chavez has neutered U.S. influence by invoking Uncle Sam’s past interventionist sins -- a task made easier by the tardy and ambiguous protest by George W. Bush’s administration of the 2002 coup that briefly ousted the democratically elected Chavez from power. But the U.S. can still do more to be an advocate for transparency and democracy. Short of meddling directly in Venezuelan affairs, it could, for example, through the media and U.S. allies disseminate more widely information that it has gathered on government corruption, Chavez’s support for Iran and Syria, and sweetheart oil deals for Russia and China. It could nominate a candidate for U.S. ambassador and put the burden of refusal on Venezuela. And, in contrast to some ill-considered legislation that threatens to strip the Organization of American States of its U.S. funding, it could offer robust support to the OAS and regional initiatives that advance shared values.

But the burden of nudging Venezuela onto a better path will rightly fall to its neighbors. This week’s summit will be gassed up with talk of the war on drugs and Cuba’s absence from the table (Chavez has pledged that this will be the last summit to which Cuba is not invited). We suggest another topic for the agenda, one apropos for a gathering hosted by a country once wracked by civil war and insurgency (and whose recovery would have been impossible without U.S. assistance): how and when Latin America should respond when one of its nations goes off the rails.

New organizations such as the Union of South American Nations and the Community of Latin American and Caribbean States seek to displace the Organization of American States, whose leadership is in need of refurbishment. And Brazil, an emerging power whose president, Dilma Rousseff, was just in Washington for talks with President Barack Obama, rightfully seeks to play a greater hemispheric and global role. Protracted violent turmoil in Venezuela -- a country with billions of dollars in resources and many ruthless “friends” -- could be the first test case for these budding forces. Let’s hope they’re ready.

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