But the two men have always managed to keep their barbs, even the most bellicose, rhetorical. Now, with the most recent spark – Venezuela on Thursday blew up two footbridges on the Táchira River – they might have a harder time backing down.
Colombia said Friday it will not be lured into conflict, but the stakes of a small-scale military confrontation are as high as they've been in recent times.
"Each time the incidents are graver," says Elsa Cardozo, an international relations expert at the Metropolitan University in Venezuela's capital, Caracas. "Something like the destruction of the bridges can make the situation more difficult. … We are very worried."
It was the latest in a string of incidents that led Mr. Chávez last week to tell his military to "prepare for war," to resist a possible US-led attack from Colombia, which last month signed a 10-year military cooperation agreement to give US troops expanded access to seven Colombian bases.
Leftist rebels, drug traffickers
Colombia claims that Venezuela is lax with drug traffickers who increasingly use the country as a transit point and permissive toward leftist rebels of the Revolutionary Armed Forces of Colombia (FARC) and the National Liberation Army (ELN) who are believed to have established rear-guard camps in the neighboring country.
On Nov. 1, two Venezuelan soldiers were killed at a border checkpoint with Colombia. In September, 10 members of an amateur Colombian soccer team were kidnapped and killed near the border. Venezuela is holding three men – two Colombians and a Venezuelan – accused of spying for Colombia, and last week Colombia's intelligence agency detained four Venezuelan national guardsmen crossing into Colombia in a motorboat.
But the bombing of the bridges ratchets up the long-simmering standoff.
The Venezuelan National Guard confirmed the destruction Thursday of two suspension bridges, claiming they were illegal border crossings used by Colombian drug traffickers and right-wing paramilitaries to cross in and out of its territory.
Alfredo Rangel, an independent security analyst in Bogotá, called the blasting of the bridges an "act of calculated hostility."
The Uribe administration called it a "unilateral and aggressive act against the civilian population" and said it would take the issue before the Organization of American States and the United Nations Security Council.
On Friday the Colombian defense minister ordered an increased presence of patrols on the Arauca River south of where the bridges were destroyed. "What's dangerous is that in a context like this anything either country does is immediately considered an aggression," says Francesca Ramos, director of the Venezuela Studies Center at the Universidad del Rosario in Bogotá.
Chávez sees US military threat
The US use of Colombian bases has been signaled by Chávez as a threat to his leftist government. He has called for a sharp reduction of bilateral trade and has "frozen" diplomatic ties with Colombia. Both Colombia and the US deny that the intention is to launch operations against a third country and say the accord aims only to fight drug trafficking and domestic insurgents.
Chávez warned President Obama last week: "Don't make the mistake of ordering an open aggression against Venezuela using Colombia."
Critics have accused Chávez of using the US-Colombia base plan to distract from problems at home. Power and water shortages have undermined his support. On Tuesday, economic news was worse than expected in the oil-exporting nation, with a 4.5 percent decline in gross domestic production in the third quarter. It was the second consecutive quarterly drop this year.
A survey by Caracas-based pollster Datanalisis, published in the Venezuelan daily El Universal in October, showed that Chávez's approval rating dropped to 46 percent from 53 percent a month earlier. More than 80 percent of those surveyed said they oppose a military conflict with Colombia.
Close business ties
That rejection is due in large part to the close ties the two countries share. Despite the heightened friction, Colombia and Venezuela continue to be each others' second-largest trade partners behind the US in both cases. That alone can act like a deterrent, says Michael Shifter, a Latin America expert at the Inter-American Dialogue in Washington. "The countries are still so deeply connected," he says.
Yet the rhetoric could lead to an accidental confrontation. "I don't think war will break out between the two countries. But one cannot discard the possibility that some border incident could lead to an armed skirmish," says Ms. Ramos.
The border between the two nations, with illegal armed groups, increased military presence, and protests over closures, makes the situation even more precarious, says Ms. Cardozo. "This is not a normal zone," she says.
And backing down for both men will likely require outside help; many observers say that the two leaders will not be able to come to terms without a third party. "If there was any situation that demands outside help and intervention, it's this one," says Mr. Shifter. "The lack of trust is so deep."
Brazil had offered to mediate between the neighboring nations but Chávez rejected any third-party arbitration out of hand. He said, however, that he would debate the issues in a multilateral forum.
On Sunday, Venezuela's Deputy Foreign Minister Francisco Arias Cardenas said the dispute should be mediated by the 12-country Union of South American Nations.
Both Uribe and Chávez are expected at a regional summit meeting on climate change in Manaus, Brazil, on Nov. 26, but the two leaders have said they will not meet one-on-one.