Colombia's presidential runoff on June 21, 2026, arrives as the country's security architecture faces its sharpest stress test since the 2016 Peace Accords dismantled the FARC-EP as a unified belligerent. With Gustavo Petro constitutionally barred from seeking a second term, the field has opened for candidates who will inherit an unresolved conflict landscape — one the accords reshaped but did not pacify.

The 2016 agreement formally ended the armed conflict with the FARC-EP and established a framework for rural reform, transitional justice, illicit crop substitution, and political participation. But the accords divided Colombian society from the outset, as CFR's 2026 analysis documents. A narrow "No" victory in the 2016 plebiscite — before the revised text was ratified by Congress — signaled that elite and popular consensus behind the settlement was fragile. That fissure never closed.

The Vacuum That Followed

Disarmament without territorial consolidation left a structural opening. When the FARC-EP demobilized, it did not dissolve the economic ecosystem it had managed: coca cultivation, extortion networks, and cross-border trafficking corridors. Dissident factions — the FARC-EP dissidents and later the Estado Mayor Central — moved to reclaim those rents, while the ELN expanded into provinces the guerrilla had previously controlled. The result, as Americas Quarterly reported in January 2026, was violence rooted partly in the power vacuum the demobilization itself created.

That dynamic is not unique to Colombia. Post-conflict power vacuums have fueled renewed fighting in Mozambique, South Sudan, and parts of the Sahel — cases where armed groups fragmented rather than disappeared after formal settlements. Colombia's version carries a particular complexity: some FARC-EP commanders who rejected the accords remained in the field, meaning the state never achieved full monopoly of force even in the immediate aftermath of the deal.

What the Next President Inherits

CFR's February 2026 report identified a genuine risk of increasing internal violence as a structural feature of the post-accords environment, not a temporary transitional phase. Rural communities in Chocó, Catatumbo, and the Pacific corridor have borne the brunt — displacement figures in those regions have tracked upward even as Bogotá has cycled through different negotiating postures with armed actors.

Petro's administration pursued a "Total Peace" (Paz Total) strategy, seeking simultaneous dialogues with multiple armed groups. The approach produced ceasefire episodes but no comprehensive settlements, and some truces collapsed under continued attacks. His successor will face a binary that Paz Total tried to sidestep: whether to prioritize military pressure or negotiated exits, knowing that neither track has delivered durable results on its own.

The election also lands at a moment of institutional strain. The Special Jurisdiction for Peace (JEP), the transitional justice body created by the accords, is processing macro-cases involving thousands of FARC-EP ex-combatants and military personnel. Its proceedings remain politically contested. Any new government that distances itself from the accords — or from the JEP's mandate — risks triggering re-armament clauses and straining the international guarantor framework that includes Norway, Cuba, and the UN verification mission.

Colombia's trajectory will also carry weight regionally. Venezuela's borderlands serve as a sanctuary for several armed groups, and the Maduro government has shown little appetite for cooperation on security. Ecuador has been drawn into spillover violence from Colombian organized crime. The next Colombian president's foreign policy calculations — whether to engage Caracas, press Washington for counter-narcotics resources, or seek renewed multilateral backing for peace implementation — will reverberate well beyond Bogotá.

The runoff does not resolve these questions. It determines who will carry them, and with what coalition behind them. Colombia's conflict has outlasted many frameworks designed to end it. The 2016 accords remain the most structurally ambitious of those attempts, even as enforcement gaps and fragmentation have prevented them from fulfilling their core promise of comprehensive peace. What the next government does with that inheritance — defend it, renegotiate it, or hollow it out — will define the country's security trajectory for the decade ahead.