Whether he is meeting farmers in the Andean mountains, flying by helicopter to visit indigenous groups in the Amazon or returning to Bogotá to shake hands with business leaders, President Juan Manuel Santos, the frontrunner in May’s elections who is hoping to win a second consecutive four-year term, gives the same message: vote for me to finish the peace talks.

The talks in Havana between the Colombian government and the FARC guerrillas seek to end one of the world’s longest-running insurgencies – a 50-year-old war, which has killed more than 200,000 people. Santos had hoped that a deal would have been struck by now, allowing him to enter elections as the man who brought peace to Colombia. Instead they have dragged on long after Santos’s November deadline and will be the biggest issue at the ballot box when the first round of voting takes place on 25 May.

“I am running because I am convinced we have advanced enough and that finally it is possible to reach that future of prosperity and peace that all Colombians deserve,” said Santos, 62, when announcing his re-election bid. “I am doing it because when you can see the light at the end of the tunnel you don’t turn back. We can’t stop half way. We have to finish this task.”

This is the first election held during a peace process but it’s not the first time the Marxist rebels have been at the centre of election campaigns and at the forefront of voters’ minds. The collapse of the last set of talks with the FARC in 2002 led to the election of the hardline Álvaro Uribe, who vowed to crush the guerrillas. Four years later, Colombians re-elected Uribe to continue his military offensive, which many felt had improved security, against the Farc.

Santos, a defence minister under Uribe, himself won election in 2010 after pledging to continue his former boss’s offensive against the rebels. But Santos changed tack after becoming president and pushed for peace. The decision to engage in peace talks with the guerrillas remains divisive. The negotiations have produced partial agreements on two of the six points on the agenda but as they have dragged on many Colombians remain at best lukewarm and, at worst, apathetic about the peace process. Polls show only a third of Colombians believe peace talks will lead to an accord.

There are other issues at stake for Colombia – and Santos believes that, peace process aside, he has a strong record. Improved security has led to record foreign investment, robust economic growth and falling unemployment rates, along with historic laws passed to compensate Colombia’s nearly six million war victims.

But a scion of an elite family, Santos lacks the populist touch and has struggled to sell this positive message, and his administration has been plagued by low approval ratings. His rather uninspiring re-election campaign slogan – “We’ve done a lot but there’s a lot more to do” – doesn’t help.

The latest polls suggest that one-third of Colombians would vote for his re-election, triggering a second-round run off in June. Putting up a strong fight is former Bogotá mayor Enrique Peñalosa, trailing second behind Santos in the polls. He’s followed by Óscar Zuluaga, a lacklustre presidential candidate, chosen by Uribe’s conservative Democratic Centre Party, who has vowed to postpone peace talks if elected.

If Santos gets re-elected, it will be seen as an endorsement for the peace talks. And if he gets an accord signed, Santos will go down as the man who brought peace to Colombia after decades of war. His legacy will hinge on the success of the peace talks.

1. Whip up momentum and support for the peace process among Colombians to ensure a referendum on any eventual peace deal will get passed.
2. Improve quality of state health services and education to avoid social unrest.
3. Building roads and giving farmers the subsidies they demand.