Carlos Antonio Lozada’s young fighters now search for their families on Facebook. Photograph by Nadège Mazars for The New Yorker

Last September, Carlos Antonio Lozada, a commander of Colombia’s FARC guerrillas, returned home to a jungle encampment in the vast wetland region called Yarí. He had spent the past two years in Havana, staying in a villa near Fidel Castro’s home, while working with other guerrilla leaders and Colombian diplomats on a peace agreement to end the FARC’s fifty-two-year insurgency—the longest in the Western Hemisphere. His time there had been gruelling: an endless succession of arguments, proposals, and counterproposals, with painful testimony from victims of both sides. “It was non-stop,” Lozada told me. At last, though, on August 24th, the two sides reached an agreement. When Lozada’s plane touched down, los camaradas—his fifty-odd personal bodyguards, young men and women who had been with him since they were little more than children—greeted him on the airstrip with a song that they had composed. “They made me cry,” he told me. “Toward the end of my time in Havana, all I could think about was being back here. The FARC is my family.”

As Lozada told me this, he was sitting in a thatched hut in Yarí, which has long been dominated by the FARC, sipping Old Parr Scotch. Communist guerrillas are not known for their fashion sense, but Lozada, a limber man with a shaved head and a small paunch, has a dandyish streak. In Havana, he wore loud tropical shirts and suède loafers. In Yarí, he favored T-shirts in hot pink, canary yellow, sky blue. With such bourgeois tastes, Lozada is an unlikely seeming Marxist revolutionary. But, at fifty-six, he is the youngest member of the seven-man secretariat that governs the FARC.

By the terms of the peace treaty, which he had helped negotiate, some seven thousand FARC fighters will submit to a process of transitional justice. In exchange for full confessions and reparations to victims, those who committed war crimes will receive “restorative sanctions,” which offer the possibility of community work rather than prison. The FARC will become a political party, and, before long, former guerrillas will be able to run for public office.

Lozada, who has spent decades shuttling between jungle outposts and Colombia’s urban power centers, is a crucial leader for the FARC as it tries to reëngage with the world. But his history also creates complications. The Colombian government has tried several times to assassinate him, most recently in 2014, when an air strike on his camp killed three of his comrades. The U.S. State Department has a $2.5-million price on his head, accusing him of trafficking hundreds of tons of cocaine to raise funds for the FARC, and of murdering hundreds of people in the process. When pressed for details of his guerrilla activities, Lozada, obeying a long-established instinct for self-preservation, likes to reply with a revolutionary maxim: “You own your secrets, but your words enslave you.”

When I visited, Lozada had spent the previous two weeks helicoptering around the country with a Colombian Army general and a group of U.N. officials, inspecting spots where guerrillas can meet and surrender their weapons. Earlier that day, he had spoken to a group of young fighters, and told them to prepare for peace. Sounding delighted, and a bit incredulous, he kept repeating, “The war is over.” Most of the combatants had been living as fugitives in their own country, and were now contemplating a return to towns and families they had not seen in years. At a nearby farm, Lozada had set up a satellite Internet connection, and he marvelled at its effect on his young fighters. “That’s all they talk about: getting on Facebook to find their parents, and making WhatsApp calls,” he said. That afternoon, the mother of one girl who had run away to join the FARC ten years earlier arrived at Yarí unannounced. When she found her daughter, she broke down. “For ten minutes, no words came,” Lozada said. “She just sobbed.”

But, after half a century of vicious conflict, family reunions do not necessarily portend an easy political reconciliation. Lozada looked out from the hut where we were sitting. Past a detachment of bodyguards, in the open kitchen of an adjacent farmhouse, guerrilla cooks stoked a fire to prepare the evening meal. A dark-green expanse of jungle stretched to the horizon. The scene was deceptively peaceful. Concealed behind the tree line, the guerrillas had war-ready camps, with trenches to foil a ground invasion and bunkers to protect against air raids. Los camaradas were readying themselves for peace, but they could also return to war if they had to, for it was war, after all, that they knew best.

Before Lozada was born, his parents lived as farmers in an area of central Colombia called Marquetalia—a mountainous, inhospitable frontier that for the Lozada family was a haven. Like other settlers, they had come in search of land and a respite from the country’s conflicts. For more than a decade, Colombia’s two major political parties, the Liberals and the Conservatives, had fought a brutal civil war, which killed at least two hundred thousand people and became known simply as La Violencia. In the late fifties, the two parties put an end to the conflict by agreeing to alternate terms in power, in a coalition called the National Front. All those outside the Front—especially those on the left—were effectively shut out.

In Marquetalia, a charismatic peasant named Manuel Marulanda organized a group of Marxist-Leninist partisans, dedicated to fighting the Front. As fears of a Cuban-style revolution grew in the capital, the government struck back, shooting and bombing. Marulanda recalled, “The state expropriated farms, cattle, pigs, and chickens from us, as they did with thousands of other compatriots.” In the early sixties, the government, backed by the U.S., sent in thousands of troops to attack the area, where the residents were guarded by some forty armed men. Marulanda and his followers fled, and, in hiding, they founded the Fuerzas Armadas Revolucionarias de Colombia—the FARC—to carry out a war against the state.

By then, Lozada’s parents had escaped to Bogotá, where his father worked as a pushcart peddler and his mother sold arepas. Lozada was born there in 1961, one of six children; his given name was Julián Gallo. His father was a member of the Communist Party, and family conversations revolved around Marxist theory, Cuba, and the Soviet Union. He joined the Party’s youth wing when he was fifteen. Soon afterward, he attended an antigovernment demonstration, and was beaten by the police and jailed for a month. Like many of his peers, he became radicalized. “Armed struggle was the order of the day,” he said. His parents warned him against joining the FARC: his mother objected on religious grounds, and his father told him that a city boy wasn’t suited to guerrilla life. Against their wishes, Lozada dropped out of school and headed for the countryside to join the guerrillas. He can still remember the date: October 20, 1978.

Lozada went for training to a FARC stronghold in a mountainous area of the Valle del Cauca, and was quickly sent into combat. The first seven or eight months—hiking through the mountains, sleeping on the ground, and eating whatever could be scrounged—were excruciating. He suffered bouts of malaria and considered quitting, but he eventually acclimatized. After three years, the FARC sent him back to Bogotá and put him in charge of the organization’s urban networks, which infiltrated universities and unions to recruit new members, gathered intelligence, raised funds, and, occasionally, launched attacks. Lozada remained in the urban underground for nineteen years, calling himself Arnulfo, or Omar, or Alberto, and telling people he met that he was a taxi-driver, a shopkeeper, or a peddler. To avoid scrutiny, he found, it was best to live in apartment buildings, where neighbors ignored one another. Even so, he changed apartments frequently. When I asked if it was awkward bumping into friends from old neighborhoods, Lozada said that no one ever seemed surprised. “It’s what people do in cities,” he said. “They move all the time.”