Colombian President Juan Manuel Santos, center, walks next to Defense Minister Juan Carlos Pinzon, second from right, during the 94th anniversary celebration of the Colombian Air Force in Bogota, Colombia, on Saturday. (Mauricio Duenas Castaneda/European Pressphoto Agency)

Negotiations with Marxist guerrillas are closer than ever to ending a 50-year conflict, Colombian President Juan Manuel Santos said in an interview after a breakthrough in talks, even as his political opponents accuse his government of selling out to the rebels.

“I think this time we will reach an agreement, and we will have peace,” Santos said, appearing relaxed, the collar of his dress shirt unbuttoned, as he flew on the presidential plane to this northern city to oversee infrastructure projects. “We have never even been close to what we have already achieved.”

The president spoke to The Washington Post two days after government and rebel negotiators announced a deal that would give guerrilla commanders a new life in politics once they disarm. The two sides will negotiate how to stamp out the cocaine trade in guerrilla territory, a critical point for the United States, which has spent billions of dollars to help Colombia eradicate drugs in those regions.

Santos said he believes that a peace deal and cessation of hostilities could take months, with negotiations in Havana likely dragging on beyond the presidential election in May. But the latest development buoyed a process that has been battered in the news media and by influential opponents led by Santos’s predecessor, Álvaro Uribe, who is now running for Senate.

“There are people who simply don’t think that what we’re doing is the correct thing to do, people who benefit from war, people who would prefer to continue what we have been suffering for the last 50 years,” Santos said. “We’re trying to give our enemies, in this case the FARC, a bridge to a dignified way out — lay down their arms and enter the political arena.”

Qualified support for talks

The talks with the FARC, or Revolutionary Armed Forces of Colombia, have come at a cost to Santos, who took office in 2010 after nearly three years as defense minister in Uribe’s government. Though 80 percent of Colombians had a favorable image of Santos in October 2012, that had fallen to 34 percent in September before rising to 55 percent after the news from Havana, according to the National Consulting Center, a Colombian pollster.

In a statement this week, Uribe lashed out after the latest revelations from Cuba, saying that it is “objectionable that democratic institutions be negotiated with FARC, the world’s biggest drug, kidnapping and murder cartel.”

Óscar Iván Zuluaga, who is the presidential hopeful for the Uribe Democratic Center party, told Reuters on Friday that rebel negotiators “should be in jail paying for their atrocious crimes.”

“They can’t be rewarded with political positions or seats in Congress,” Zuluaga said. “With terrorism, the only thing we can discuss is submission.”

The public here overwhelmingly supports peace talks, but a majority of Colombians believe the negotiations in Havana will not end the conflict, polls show. That view seemed to harden in recent months with news of FARC attacks on security forces and with the publication of images of rebel commanders in Havana, which in recent days included a photo of three guerrilla negotiators lolling on a yacht.

Santos, 62, who is expected to run for reelection, said he understood his countrymen’s frustration. “People are eager to have more results,” he acknowledged.

But he asked for patience and said that the final outcome will be highly beneficial to this country of 47 million, which has lost 220,000 lives in a simmering conflict that has mostly touched the poor in the countryside.

“They are going to have space in our democracy to pursue their objectives; I think this is something obvious and completely normal in a process of this sort,” Santos said. “Will they have seats in Congress? I personally prefer the FARC being in Congress than shooting and creating violence and trafficking in drugs.”

Awaiting what’s next

The details of exactly how the FARC will participate in politics have not yet been released, but the president spoke of broader representation in remote regions and looser restrictions for those forming political parties. The two sides in May also reached a partial agreement on a rural development policy to benefit poor farmers.

Now Colombians, along with the Obama administration, will be closely following the next issue at the peace talks: how to address the cocaine trade.

Since 2000, the United States has spent about $10 billion in training and equipment for Colombian security forces and in aircraft and helicopters for anti-narcotics forces that strike directly at coca plantations. Called Plan Colombia, the strategy has reduced the size of Colombia’s coca crop to a third of what it was in 2001, weakening the rebels and other groups that have benefited from drugs.

Santos said the objective in Havana is to create a plan that would incorporate the FARC, which his government had long accused of being a cocaine cartel, into efforts to further reduce the size of coca plantations.

“If they become our allies in order to destroy and eradicate these coca fields and destroy the corridors, can you imagine, not only for Colombia but for the whole world, what this means?” Santos said. “It would be a major, major achievement.”