Guillermo León Sáenz, alias "Alfonso Cano," the leader of the Revolutionary Armed Forces of Colombia (FARC), was shot and killed on Nov. 4 during Operation Odiseo, a joint air force-army raid that was triggered after police intelligence traced Cano´s location through an intercepted phone call. Following this blow to the already weakened FARC, Colombia now faces the best opportunity in decades to end Latin America´s longest and most intractable conflict.

Cano, who succeeded long-serving FARC commander "Manuel Marulanda" in 2008, is the first ever Colombian guerrilla chief to be killed in combat. With his demise, FARC has lost not only its military head but also its most prominent political leader and chief ideologue -- a man who studied anthropology and law at university and was a committed communist before becoming a guerrilla.

The unprecedented operation will give a boost to President Juan Manuel Santos, who was battling deteriorating security conditions and demonstrations by remaining FARC forces in places like Cauca, Catatumbo, and Arauca, which had prompted him to replace his defense minister and the military command structure in late August. Somewhat ironically, Cano´s death also represents a blow for Álvaro Uribe, the president´s hard-line predecessor, who has transformed into a vocal critic of the government and who had recently suggested that the morale in the armed forces was dwindling under Santos. Cano´s death will quiet such speculations.

Cano´s passing, which follows a series of deaths of high-ranking FARC leaders over the last three years, has brought the group to its weakest point in its 47-year history. But it will not precipitate an overnight collapse. Led by a seven-member secretariat, FARC has shown in the past that it is able to overcome leadership losses and adapt to changing circumstances. After several near misses over the last two years, Cano´s killing is not unexpected, and FARC might well have contingency plans at hand.

But given the strain inflicted by the relentless military pressure over the last years, FARC will struggle to replace him. The key question will be whether the new leader has a strong enough grip over the group to maintain its cohesion, preventing it from disintegrating into uncoordinated units driven entirely by criminal business interests. As no replacement will have the internal standing of Cano, who spent 33 years as a guerrilla, this risk is real.

His removal, however, could also pave the way for the appointment of a less intransigent leader. The leadership contest will probably come down to two secretariat members who go by the aliases Timochenko and Iván Márquez. Compared with Cano, who could not shake his reputation as a radical, both of these men could be more receptive to a negotiated end to the conflict. Marquez, in particular, played a prominent role in the Caguán negotiations that ended in 2002.

With both thought to be hiding in the border region with Venezuela, the focus of the conflict could shift from the southwestern to eastern regions of Colombia. Relations with Venezuela have improved under Santos, but sustained military pressure on the border could once again complicate them. The government must also carefully manage the information seized in the Cano raid, which includes seven computers, 39 USB sticks, and 24 hard disks. It will want to avoid repeating the controversy that was set off by the information found in 2008 on the computers of the FARC commander who went by the alias Raúl Reyes. (Having been seized by military officials, rather than the judicial police, the Colombian Supreme Court ruled that the evidence was illegally obtained and inadmissible in court cases.)

The post-Cano era is of course not risk free, but there are signs that the new government is up to the task. Encouragingly, both Defense Minister Juan Carlos Pinzón and Santos responded to the news with moderation, with the latter explicitly warning against unwarranted triumphalism and committing to "insist until delivering a country in peace to the Colombians." Importantly, political leaders have reacted to Cano´s death by seeing it as an opportunity to disarm and reintegrate the estimated 7,000 FARC combatants, rather than as a sign for an imminent military victory.

This reaction likely reflects a growing consensus that some form of negotiations will be needed to end the conflict. The operation also comes against the background of moves in Colombia´s Congress to pass a law that would facilitate peace negotiations with the guerrillas.

At long last, the end of Colombia´s long and bloody guerrilla war is in sight. On Oct. 30, Gustavo Petro, a former member of the demobilized 19th of April guerrilla movement (M-19), was elected mayor of Bogotá, the country´s second-most important political position. Not one week later, the death of Alfonso Cano has shifted the balance of power -- probably irreversibly -- in favor of the government. There may well be a period ahead of heightened military confrontation as FARC tries to show that it is not yet a spent force and as a new leader attempts to establish authority internally, but this should not prevent both sides from intensifying back-channel contacts to lay the foundations for talks. Never has it been clearer that democracy and negotiations are the only ways forward in Colombia -- the government shouldn´t let this historic moment pass it by.