The damage from Sunday’s vote is still sinking in. Instead of winning by an almost two-to-one margin as pre-election polls had predicted, those favoring the accord with the Revolutionary Armed Forces of Colombia lost by a razor-thin margin, 49.8 percent of the votes to 50.2 percent for those against the deal.

Both President Juan Manuel Santos and leaders of the FARC, having come this far after four years of grueling 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 given the stunning political defeat he suffered. For now, he has ordered his negotiators to return to Cuba on Monday to confer with FARC’s top leaders, who watched the results come in with disbelief after earlier 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 later.

The loss for the government was even more shocking considering the huge support for the accord among foreign leaders, who have roundly 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.

With the outlook uncertain, all eyes are on Santos’ former boss and chief rival: Alvaro Uribe, the powerful former president who 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.

Uribe, in prepared remarks from his ranch outside Medellin after the results were in, called for a “big national pact” and 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, and took more swipes at the FARC, who he demanded put an end to drug-trafficking and extortion.

“The entire accord was full of impunity,” said Ricardo Bernal, 60, celebrating the victory for the “no” side in a Bogota neighborhood where opponents were gathered. “We all want peace but there has to be adjustments made.”

Across town, hundreds of supporters of the peace deal who had gathered in a hotel ballroom for what they expected would be a victory party with Santos wept in despair.

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.” The president, who has a little under two years left in office, could also seek to bypass another popular vote and ratify the accord in congress or by calling a constitutional convention, something both the FARC and Uribe have previously favored.

“I’ve always believed in a wise Chinese proverb to look for opportunities in any situation. And here we have an opportunity that’s opening up, with the new political reality that has demonstrated itself in the referendum,” Santos said Sunday night before descending to the steps of the presidential palace to address a small group of supporters, some of waving white flags symbolizing peace.

But bringing Santos and Uribe together might be harder than achieving peace with the FARC. Santos served as Uribe’s defense minister, when they worked together with the U.S. to drive the FARC to the edge of the jungles, but the two haven’t spoken for years and frequently trade insults.

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 ambitious accord was lacking. Heavy rains from Hurricane Matthew especially dampened voting along the Caribbean coast, where the government’s electoral machinery is strongest and the “yes” vote won by a comfortable double-digit margin.

The campaign exposed deep rifts in Colombian society, dividing many families and 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.

“In the end, hate toward the FARC won out over hope for the future,” said Jason Marczack, an expert on Latin America at the Washington-based Atlantic Council.

Story: Joshua Goodman, Andrew Rodriguez; additional reporting Michael Weissenstein