By Nelson Acosta
HAVANA (Reuters) - The chances for a "stable and lasting peace" have never been better, Colombian rebels said before peace talks on Wednesday in the latest sign that President Juan Manuel Santos could receive a boost from the negotiations ahead of the May 25 election.
Santos, engaged in a tightening re-election campaign, might benefit from any breakthrough between now and the first round of presidential elections, in which his leading rival has threatened to break off peace talks.
The Revolutionary Armed Forces of Colombia (FARC) and the Colombian government have held talks in Havana over the last year and a half, seeking to end 50 years of conflict.
"There are possibilities for a stable and lasting peace in Colombia like never before, but obviously there have to be mutual concessions," Rodrigo Granda, a member of the FARC negotiating team, told reporters in Havana.
"Whoever breaks this peace process in Havana, no matter who the president is, will have to pay a very high political price, an enormous one," Granda said just before sitting down with the government.
The two sides are working a partial accord on eradicating illegal drug crops, which would be the third of five major agreements that would then be revisited in a sixth and final phase of a comprehensive agreement.
The FARC has battled a dozen Colombian governments in a Marxist-inspired struggle against inequality. It has also turned to kidnapping and coca production to finance itself.
Santos, of the center-right, has bet his political legacy on bringing peace to the Andean nation and said the FARC has little choice but to turn in their weapons.
His once solid lead in public opinion polls has disappeared, and right-wing rival Oscar Ivan Zuluaga has closed the gap. Although Santos still leads in most surveys, a poll released by Centro Nacional de Consultoria (CNC) on Tuesday showed Zuluaga with a slight lead.
Zuluaga belongs to the party of former President Alvaro Uribe, whose popularity rose by taking a hard line against the FARC. Zuluaga has threatened to break off peace talks if he wins and the FARC does not declare a unilateral cease-fire.
Neither Santos nor Zuluaga appears likely to receive the 50 percent of the vote needed to win in the first round, in which case the election will be decided in a second round between the top two finalists on June 15.
(Reporting by Nelson Acosta; Editing by Daniel Trotta and Gunna Dickson)