On October 2, 2016, Colombians will be given a chance in a national plebiscite to embrace or reject a peace accord negotiated over four years between the government of President Juan Manuel Santos and the country's largest insurgent group, the Revolutionary Armed Forces of Colombia (FARC). The FARC has fought the Colombian government for more than five decades and funded its leftist insurgency with proceeds from extortion, drug trafficking, and other illicit activities.

The vote is not legally required to approve the FARC-government negotiations but was the path chosen by the Santos government to garner public support and bring legitimacy to the result. Despite the complexity and slow pace of peace negotiations, which lasted for some 50 "rounds" of talks, the process came to a rapid close with these major developments:

Momentum Toward Ending the War

Between September 17 and September 23, 2016, the FARC guerrilla forces and leadership are scheduled to convene what is technically their 10th conference to determine their support for the accord. The peace accord stipulates that FARC combatants will disarm within 180 days of signature. FARC fighters are to move to zones in 28 sites around rural Colombia to disarm in a U.N.-supervised process. An estimated 10,000 to 15,000 FARC fighters and militia members would then begin a process of reintegration into civilian life.

An ambitious program of transitional justice would take place through a mechanism called the Special Jurisdiction of Peace (JEP), featuring a Tribunal for Peace made up of judges selected by Colombian judges and foreign dignitaries, including the U.N. Secretary General. According to some estimates from Colombia, roughly 1,000 FARC members may be tried for serious crimes, including war crimes. If the perpetrators fully confess and pay victims reparations, they could become eligible for alternative sentences through the JEP that would not require serving time in a traditional jail but would restrict the liberties of those convicted. A parallel but "differentiated" process is to apply to the government security forces convicted of violations.

Potential Disrupters

Most observers anticipate that the majority of the FARC will agree to the terms of the peace agreement, but whether the Colombian public will vote in favor of the accord is less certain. Some analysts maintain that the Colombian public's discomfort with the agreement's terms will overshadow a desire to end the conflict. They highlight the public's concern about justice for crimes committed during the war and the guaranteed political representation of the FARC in the Colombian Congress as support-draining concessions. Under the accord, the FARC would have a total of 10 guaranteed seats in Colombia's House and Senate in legislative elections in 2018 and 2022. Other observers contend that although the accord is far from a perfect deal, it would allow Colombia to achieve peace.

The accord will be expensive and difficult to implement. Several major challenges, in addition to the costs of implementation, which are not fully tallied, are described below.

No Vote. What is the likelihood that voters will surprise forecasters by voting against the accord? Polls initially showed considerable variability in public opinion toward the plebiscite, with some indicating a triumph for a "no" vote against the accord and others showing a narrow win for supporters of the accord. The Colombian government notes that the "yes" vote appears to be gaining ground, and several mid-September polls indicate that Colombians now support the accord by a two-to-one margin. Other media accounts suggest that 20% to 30% of Colombians remain undecided. The Santos Administration states that there is no "Plan B"—if the plebiscite is voted down, a return to war is likely.

Border Area Instability and Other Armed Actors. Many insurgents from the FARC and the smaller National Liberation Army (ELN) occupy regions along Colombia's borders with Ecuador and Venezuela. Insurgents use the permeable borders to elude prosecution and raise funds. The ELN began preliminary talks with the Santos government, but as of September 2016, no formal peace talks have occurred. Meanwhile, the ELN continues to kidnap and blow up oil and energy infrastructure, mainly in its area of influence in northern Colombia, and it imposed an armed blockade in several states in mid-September 2016. Some analysts contend that the ELN will continue to expand and recruit former FARC combatants into its ranks. Others believe the ELN and FARC dissidents will relocate their bases to neighboring countries and continue to undermine peace efforts.

Colombia's peace process may face an enormous challenge due to the instability of Venezuela, with Venezuelans coming over the border to seek jobs, food, and respite from crime. Venezuela was once one of Colombia's strongest trade partners and a key supporter of peace negotiations. Armed criminal bands of former right-wing paramilitaries also reside near the border with Venezuela.

Coca, Cocaine, and Future Violence. The United Nations (U.N.) and the U.S. government reported an explosion of illicit drug cultivation in Colombia in 2015, particularly in coca bush and cocaine derived from it. The surge in cultivation generated between 46% and 68% more cocaine than the prior year, according to the respective U.N. and U.S. estimates. For the most part, Colombia has not followed through on its commitment to implement drug crop eradication, alternative development, and licit livelihoods programs, despite the country's decision to end aerial spraying of coca crops and introduce a new drug policy. Colombia's potential peace dividend in reduced violence may not be realized for some time. Other armed criminal groups are likely to take over coca cultivation, cocaine production, and trafficking routes abandoned by the FARC. As those groups struggle to solidify their control, some analysts expect violence to climb rather than decline.