By Helen Murphy and Luis Jaime Acosta
Cesar Gonzalez is proud of his tin-roofed cabin in the warm hills of central Colombia. Clothes hang neatly along the wall and shelves are lined with coffee and sugar jars. He has two beds, a gas stove and a fridge.
It is a far cry from his life up until two years ago as a rebel fighter in the ranks of the Revolutionary Armed Forces of Colombia (FARC), the 62-year-old said.
Back then, Gonzalez slept on a pile of leaves beneath a lean-to covered by plastic sheeting. His days were spent with an AK-47 automatic assault rifle strapped to his back in the frigid ranges of Colombia's eastern Andes.
Some 12,000 members of the Marxist rebel group, like Gonzalez, handed in their weapons after a 2016 peace deal. Many now live in two dozen reintegration camps scattered across Colombia, including the one Gonzalez now calls home near the town of Icononzo in Tolima province.
But Sunday's presidential election has shaken the fragile peace accord as right-wing front-runner Ivan Duque threatens to overhaul a deal he deems too lenient on the former Marxist rebels.
Duque and his Democratic Center party want to scrap an amnesty for FARC commanders who committed crimes, including engagement in the cocaine trafficking that helped bankroll the group, and prevent them from participating in politics until they serve out prison sentences.
For many Colombians, that has stirred fears the FARC could return to five decades of violence in which more than 220,000 people were killed and millions displaced. (Special Report-A fractured peace https://www.reuters.com/investigates/special-report/colombia-peace)
Demobilized FARC fighters, including the group's leader Rodrigo Londono, known by his nom de guerre Timochenko, insist that Duque would be unable to scrap the amnesty, and Colombia's top court has ruled that the peace accord cannot be altered.
Former insurgents told Reuters during recent visits to two reintegration camps, about 370 miles (600 km) apart in central and southern Colombia, they see no path back to violence for the FARC.
Some former fighters have drifted into criminal gangs, however, and tensions fueled by Latin America's longest-running armed conflict still run high in a country marked by gaping inequality.
"We guerrillas don't want war. We want peace," said Gonzalez, who spent 31 years in rebel ranks. "Enemies of peace always want to change course, to live in the era of violence."
The peace deal, which earned President Juan Manuel Santos the 2016 Nobel Prize, offered the rebels pay and benefits if they came clean about their crimes and compensate victims with land and other assets they held.
The accord allowed the FARC to create a political party, the Revolutionary Alternative Common Force, and automatically gave it 10 seats in Congress for eight years. The party, known by the same Spanish-language acronym as the once feared guerrilla group, failed to win any additional seats in March legislative elections.
Duque, a 41-year-old protege of former President Alvaro Uribe, whose hard line offensive against the rebels helped push them to the negotiating table, has said he is incensed there were now "criminals" in Congress shaping laws after decades of kidnapping, extortion and killing.
The FARC says Duque's calls for change in the peace accord threatens to slow down the deal's implementation. Apart from denting morale, that could lead to more individuals withdrawing from the deal and turning to illegal activities like drug trafficking and coca cultivation to make a living.
Production of coca, the raw material for cocaine, is booming once again across Colombia.
Leftist presidential hopeful Gustavo Petro, who trails Duque by almost 20 points in polls, has criticized the peace agreement for making only tentative attempts to tackle rural inequality but has said he will leave it intact.
In an interview with Reuters, in a remote camp in southern Putumayo province near Colombia's border with Ecuador, FARC chieftain Londono spoke adamantly about the accord he helped negotiate in Cuba.
"We've achieved a peace process that stopped the war," the bespectacled 59-year-old said. "The right may put the peace process at risk but they cannot destroy it."
Wearing jeans and a blue embroidered shirt, Londono, who has shaved his trademark beard and now sports a pencil mustache, said Duque was trying to "sabotage" the accord but his rhetoric may change if he becomes president.
MILLIONS DESPERATE FOR PEACE
With anger simmering over crimes committed during the war, the peace deal has proven divisive. It was narrowly rejected in a 2016 referendum before a modified version was approved by Congress. Yet millions of Colombians remain desperate for a new start in a nation torn by decades of political bloodletting.
Some centrist voters are reluctantly backing Petro, 58, solely for his support of the deal, despite his radical pledges to redistribute land and diversify the economy away from oil and coal, the country's major exports.
In an effort to win wavering voters, Duque, a former senator, appears lately to have softened his stance.
"It's not about destroying the agreement but about making modifications," Duque told Reuters in a recent interview.
He said he would alter the peace accord by forging alliances in Congress, where his party holds just 51 of 280 seats, and by generating a national consensus.
"It's about ... guaranteeing peace with justice," Duque said, adding he would seek "appropriate penalties," particularly for crimes against humanity.
While Duque may make minor changes to the peace accord, it would be almost impossible for him to make substantive alterations to something backed by about three-quarters of Congress, said Rodrigo Pombo, a constitutional law expert.
"Destroying the peace agreements is impossible because they have politically irreversible aspects," he said.
The constitutional court, where eight out of nine justices broadly support the agreement, is a major obstacle for Duque. The court has ruled the deal cannot be modified for 12 years.
Duque could convene a constituent assembly or seek a referendum to decide changes. But, as Santos discovered when Colombians rejected the original deal, a vote would be unpredictable.
If elected, Duque has promised a constitutional reform to prevent drug trafficking from receiving amnesty under any circumstance.
It is a sensitive issue. FARC political leader Ivan Marquez warned in April he may not take his senate seat in protest at the arrest of another former rebel on U.S. drug charges - even though the alleged crimes came after the war ended.
The United States provides $400 million annually to fight trafficking in the world's top cocaine producer.
Ultimately, Duque may opt to stall implementation of the accords by strangling funding, leaving the FARC in limbo and unable to launch planned agricultural projects designed to substitute coca cultivation.
That could drive many to abandon the movement and return home or join the ranks of dissident groups.
More than 1,200 FARC remain armed despite the peace agreement. With coca cultivation doubling in the last three years, many are involved in trafficking and have launched attacks against military and civilian targets.
While some victims of FARC atrocities support Duque's calls for tougher justice, many who live in conflict zones are more sanguine.
When rebels bombed the impoverished town of Bojaya on Colombia's northwest coast 16 years ago, killing nearly 90 people in one of the war's worst civilian massacres, Leyner Palacios, 42, saw dozens of friends and relatives die.
He is now alarmed that new groups, including paramilitary organizations, are gaining strength amid talk of a return to war.
"Just the hint that this peace process could fail has revived the violence," he said.
(For a Graphic on Latin American elections https://tmsnrt.rs/2rAQ4l1)
(Reporting by Helen Murphy; Editing by Daniel Flynn and Tom Brown)