FARC Rebels Vow To Continue Fight

"He was completely anchored in the past, with an archaic vision of the world and the country, and he many times impeded advances in peace negotiations," Santos said of Marulanda in an interview. "He was a very shrewd person but very elemental person, not very sophisticated in his intellectual preparations and intellectual visions, so he had been a stumbling block."

Sáenz Vargas, better known by the alias Alfonso Cano, is considered the FARC's top Marxist ideologue and had been a Communist Party politician. His main rival is the FARC's top military commander, Jorge Briceño, a rotund man best known as the FARC's leading military tactician.

Briceño, whose nom de guerre is Mono Jo Joy, oversaw a military expansion in the 1990s and helped plan some of the group's biggest victories against the army that decade. The military high command believes that the decision to choose Sáenz Vargas could touch off a struggle within the FARC.

"Mono Jo Joy, who many thought was going to be the successor of Marulanda, had never had the best of relations with Alfonso Cano," Santos said. "And we might see an internal conflict between those two, between the political side and the military side."

It is difficult to predict the actions of a group that is considered among the most hermetic in the long line of Latin American insurgencies. Even those with a direct channel to the rebel command are unable to say what decisions might be taken.

Álvaro Jimenéz, a former guerrilla with the now-demobilized M-19 rebel movement, said Cano, who studied at Bogota's National University and oversees the FARC's clandestine political cells, could provide fresh ideas to the rebel movement.

"Alfonso Cano is the man who can have a better connection to the country we are today, who can best interpret the point of view that Colombians have in wanting an end to this conflict," he said.

The Colombian government, though, also has to show it is willing to reach a negotiated solution to the conflict. Jimenéz said that although high officials say Uribe is open to talks, the president's hard-line rhetoric against his opponents has created political polarization that is not conducive to negotiations.

Senator Gustavo Petro, of the center-left Polo Democratic Party, said the government cannot assume its recent successes against the FARC will push the group into talks. He said the FARC must be induced to the negotiating table with a viable peace offering. Otherwise, he said, the conflict could continue, even if the FARC does begin to splinter.

"Uribe right now projects war, and the war route just generates more war," Petro said. "That could, of course, lead to a military triumph. Or the perpetuation of war."