By Helen Murphy and Luis Jaime Acosta
VILLAVICENCIO, Colombia, May 8 (Reuters) - Peace talks to end five decades of war are on the line in Colombia's election this month with President Juan Manuel Santos fighting for a second term while opponents accuse him of giving up too much to Marxist rebels at the negotiating table.
Just three weeks shy of voting, the battle between the top two candidates has heated up and the peace talks are at the center of the campaign.
Santos is staking his reputation on negotiating a deal with guerrilla leaders of the Revolutionary Armed Forces of Colombia, (FARC) but his main right-wing rival, Oscar Ivan Zuluaga, says the peace process is deeply flawed.
Santos says the talks could collapse if he is not re-elected on May 25.
"I'd rather it wasn't like that, but with other people this peace process wouldn't have the same future," he told Reuters on Tuesday in the central city of Villavicencio. "There are candidates who have openly said they would break talks, so ultimately this comes down to a choice between war and peace."
Santos, a 62-year-old economist and consummate political insider, launched the talks with the FARC at the end of 2012 with heavy popular support. Pledging an accord could come within a year, he kept up battlefield pressure by refusing a ceasefire until all five points on the agenda were agreed.
Since then, partial deals have been reached on agricultural reform and the rebels' participation in politics but they have not yet agreed on how to end the illegal drugs trade, which the FARC is involved in.
The other two key issues will be reparations for war victims and the mechanics of ending a conflict that has killed more than 200,000 people since the FARC took up arms in 1964.
Many Colombians suspect the rebels could be stringing along the government for political gain and have no intention of giving up their weapons after 50 years of war.
Zuluaga and his powerful ally, former President Alvaro Uribe, have led criticism of Santos' peace efforts, furious that veteran FARC leaders were free in Havana while their fighters continued to kill in Colombia.
Zuluaga says he also wants peace but that the rebels must lay down their weapons before any negotiations and that they must face prison time for their crimes. He appears to favor a battlefield solution.
"The only thing we can discuss is submission," Zuluaga, a former finance minister, told Reuters in a November interview.
TOO SOFT ON REBELS?
Details of the peace talks are confidential but Zuluaga has accused Santos of offering FARC leaders seats in Congress and a get-out-of-jail-free card if they sign an accord.
He insists the president is putting his own desire for a place in the history books as the man who brought peace to Colombia above the country's real needs.
Zuluaga and Uribe remind voters that previous peace efforts strengthened the FARC and that it was Uribe's uncompromising policies in 2002-2010, when Santos was his defense minister, that saw the biggest military gains against the rebels.
But their cause was hurt this week when a member of Zuluaga's social media team was accused of hacking into FARC negotiators' email accounts in what Colombia's chief prosecutor said was an attempt to disrupt the talks.
Zuluaga's campaign chief resigned late on Wednesday. That came just days after Santos' campaign strategist quit amid allegations he took a bribe to prevent a suspected drug trafficker being extradited to the United States.
Opinion polls show Santos, a center-rightist and close ally of the United States, with a clear lead over Zuluaga but falling short of the 50 percent he would need to take victory in the first round. If he fails, he would almost certainly face Zuluaga in a run-off.
Although Zuluaga has taken a hard line on peace talks, analysts said he would likely pay a high political cost if he were to cut them off. If he wins the election, he might instead seek to pressure the FARC into meeting his demands - a unilateral ceasefire and a map of where landmines are planted - as a condition for continued negotiations.
"Zuluaga as president certainly raises the risk that talks could collapse but he's more pragmatic than that so he may use his position to get more from the FARC," said analyst Juan Carlos Palou. "It could turn into a game of chicken."
Santos says any failure to strike a peace deal now would inevitably mean more political violence.
"If there is no deal, we will go back to the same situation we were in before we initiated the process," he said, adding that any peace deal would go to a referendum for approval.
"If peace is rejected, well, we will continue at war, but it wouldn't be very rational that a society votes to continue war instead of living in peace."
(Reporting by Helen Murphy; Editing by Kieran Murray)