Instead of winning by an almost two-to-one margin on Sunday as pre-election polls had predicted, the accord with the Revolutionary Armed Forces of Colombia (FARC) lost by a razor-thin margin, 49.8 percent to 50.2 percent. Both President Juan Manuel Santos and leaders of the FARC, after four years of gruelling negotiations, vowed to push ahead, giving no hint they want to resume a war that has already killed 220,000 people and displaced 8 million. “I won’t give up. I’ll continue search for peace until the last moment of my mandate,” Santos said in a televised address appealing for calm. But it’s not clear how the already unpopular Santos can save the deal following the political earthquake, comparable to Britain’s vote to exit the European Union. His chief negotiator, Humberto de la Calle, offered his resignation Monday, assuming what he called “complete responsibility” for the defeat. It’s unclear whether Santos will accept the offer or, as he previously announced, send him to Cuba with other negotiators to confer with FARC’s top leaders, who watched the results with disbelief after ordering drinks and cigars at Club Havana, once Cuba’s most exclusive beach club. “The FARC deeply regret that the destructive power of those who sow hatred and revenge have influenced the Colombian people’s opinion,” the FARC’s top commander, a guerrilla known as Timochenko, told reporters. The loss for the government was even more shocking considering the huge support for the accord among foreign leaders, who have heralded it as a model for a world beset by political violence and terrorism. Many heads of state as well as U.N. Secretary-General Ban Ki-moon and U.S. Secretary of State John Kerry were present when Santos and Timochenko signed the deal less than a week ago in an elaborate, emotion-filled ceremony in the historic city of Cartagena. “In Cartagena, I witnessed the profound desire of the Colombian people to end the violence,” Ban Ki-moon told reporters in Geneva. U.S. State Department spokesman John Kirby also expressed backing for Santos’ plan for “a broad dialogue” in the search for peace. “Colombians have expressed their commitment to settle their differences through institutions and dialogue rather than violence,” he said. Santos’ former boss and chief rival, former President Alvaro Uribe, led the grass-roots campaign against the accord. With none of the government’s huge PR machine, an angry Uribe gave voice to millions of Colombians, many of them victims of the FARC like him, who bristled at provisions in the 297-page accord sparing rebels jail time if they confessed their crimes and instead reserved them 10 seats in Congress. After the results were in, Uribe insisted on “correctives” that guarantee respect for the constitution, respect for private enterprise and justice without impunity. But he didn’t specify whether he would join Santos in trying to salvage the deal. The FARC’s 7,000 guerrilla fighters are unlikely to return to the battlefield any time soon. For now, a cease-fire remains in place. One option for Santos would be to reopen negotiations, something he had ruled out previously and his chief negotiator said would be “catastrophic.” One of the reasons for the surprise defeat was low turnout, with only 37 percent of the electorate bothering to vote, a further sign to some analysts that Colombians’ enthusiasm for the accord was lacking. The campaign exposed deep rifts in Colombian society, dividing many families. making clear the road to reconciliation would have been long and torturous even had the accord passed. Colombians overwhelmingly loathe the FARC, which the U.S. considers a terrorist group, and many considered the accord an insult to victims of the long-running conflict. But while urban voters who were being leaned on to pay for the peace largely voted against the accord, victims in many areas hardest hit by the conflict overwhelmingly endorsed it.