Colombians look set to back a peace accord with Marxist rebels in a referendum on Sunday, the final hurdle for a deal that would end 52 years of war and allows FARC fighters to re-enter society and form a political party.

The plebiscite asks for a simple ‘yes’ or ‘no’ on whether Colombians support the accord signed on Monday by President Juan Manuel Santos, who has staked his legacy on peace, and the rebel commander known as Timochenko.

‘We must end a 52-year war and open the way to peace, a peace that will take us to a better future ... peace is the way to ensure our children and grandchildren have a better country,’ Santos said after voting.

The Revolutionary Armed Forces of Colombia, known as FARC, whose numbers halved to about 7,000 in recent years due to a US-backed military offensive, have agreed to turn in weapons and fight for power at the ballot box instead of with bullets.

After four years of negotiations in Havana, the final agreement was applauded around the world. Recent polls show about two-thirds of voters are likely to ratify it.

Influential former President Alvaro Uribe has led the ‘no’ camp, arguing that rebels should pay for crimes in jail and never be given congressional seats. But most Colombians, including some who see the accord as too soft on the FARC, seem convinced that an imperfect peace is better than more war.

‘This country needs a change and it has to be today, Fabiel Cruz, 31, an administrator, said after voting yes. ‘It's the only chance we have. If it's not today it will be never,’

Under the accord, the FARC, which began as a peasant revolt in 1964, can compete in the 2018 presidential and legislative elections and will have 10 unelected congressional seats guaranteed through 2026.

The FARC's Marxist rhetoric goes very much against the beliefs of the largely conservative Colombian population and most, including Santos, think they will have difficulty finding a political footing.

But while the number of seats is not enough to sway legislation, some are still outraged.

‘I voted no. I don't want to teach my children that everything can be forgiven,’ said Alejandro Jaramillo, 35, angered that the rebels will not serve jail time.

‘The accord gives a lot of concessions to the guerrillas. They changed their strategy from arms to politics but the goal is still socialism,’ said Javier Milanes, 34, a restaurant owner who also voted no.

For decades, the FARC bankrolled the longest-running conflict in the Americas through the illegal drug trade, kidnapping and extortion, spreading a sense of terror that left few Colombians unaffected. The conflict claimed more than 220,000 lives and displaced millions of people.

If the peace accord is approved on Sunday, Santos likely will turn his focus toward a much-needed tax reform and other measures to compensate for a drop in oil income, as well as possible talks with the smaller ELN rebel group.

Voting closes at 4 p.m. local time (2100 GMT) and results are expected by early evening.