After mud-slinging campaign, ex-leader's shadow looms over presidential election in Colombia

Colombia's nastiest presidential campaign in years has focused largely on a single issue: incumbent Juan Manuel Santos' prescription for ending the nation's half-century-old guerrilla conflict.

The patrician, U.S.-educated incumbent says peace is near after 18 months of slow-going talks in Cuba that he had hoped to wrap up months ago.

Challener Oscar Ivan Zuluaga accuses Santos of selling the country out to an insurgency that is already on the ropes.

The hand-picked candidate of former President Alvaro Uribe won the most votes among the five candidates in the election's first round on May 25. Polls show a tight race in Sunday's runoff.