The stakes are high for more than 36 million Colombians heading to the polls, Sunday, June 17, to elect their next president.

Three weeks after the right-wing candidate Iván Duque of Centro Democrático party secured 39% of the vote compared with 25% for leftist Gustavo Petro, in the first round May 27, the former mayor of Bogotá has received wide-spread support on social media for his Colombia Humana coalition.

Even though Duque, the 41-year old Bogotá economist has been leading in the polls with a six to 15 point advantage over Petro, the difference on Sunday may come down to only several percentage points, as the former M-19 guerrilla has received the endorsement of well-known intellectuals, musicians, animal rights groups and unionists.

Neither Iván Duque nor Gustavo Petro publicly debated each other in the three weeks leading to Sunday’s final election.

As voting begins 8 am Sunday (with polls open until 4 pm local), the first official bulletins from the National Registry will be announced almost immediately, and a total vote count expected around 6 pm.

Both candidates will cast their ballot in the capital city, Bogotá. Voting is also under way in 69 countries.

A ban on alcohol sales and consumption is in effect as of Saturday 6 pm until Monday 6 am. Colombia’s overland borders with Ecuador, Venezuela and Brazil are closed during Sunday’s election hours.

In what is considered the most polarized election in recent history, the runoff pitches two contrasting economic models against each other: the socialist doctrine of Petro and pro-investment vision of Duque. “This election goes way beyond deciding on the future of the peace process with FARC,” claims Hugo Mestre, a small business proprietor in Bogotá. “It determines if I can keep my business going in Colombia.”

Many of Duque’s conservative followers believe a Petro government will result in heavy tax increases for the “rich” and stump foreign investment. Those on the left believe, the right-wing candidate who worked at the Inter-American Development Bank in Washington, D.C., represents the interests of “corrupt” industrial elites and is a pawn of the strong-handed former president Álvaro Uribe Vélez, who governed Colombia between 2002 and 2010, and waged a military offensive against the country’s largest guerrilla insurgency the Revolutionary Armed Forces of Colombia (FARC).

The possibility of a Petro “upset” victory has sent jitters through the investment community, and financial analysts have speculated that should the leftist candidate win on Sunday, the country’s tightly managed macro-economic model could be thrown into turmoil.

Those on the left claim that a Duque administration will further institutionalize social and economic inequality. Petro, during the three week runoff campaign, has softened his stance on proposing a Constituent Assembly to reform the country’s legislative system and expropriating land and businesses not considered “productive.” Duque supporters insist a Petro government will plunge Colombia into a Venezuela-style economic catastrophe, citing the former M-19 guerrilla’s ineffective term as mayor of Bogotá from 2012 to 2015 in which he annulled private garbage-collection contracts to favor the district’s trash management. Colombia’s largest city was engulfed in a garbage crisis in which Petro justified his move with divisive class-based rhetoric.

During the first election round, Iván Duque and vice-presidential running mate Martha Lucía Ramírez secured 7,4 million votes. Gustavo Petro and his vice presidential formula Ángela María Robledo clinched the runoff with 4,8 million.