BOGOTA, Colombia — Juan Manuel Santos convincingly won re-election Sunday after Colombia’s tightest presidential contest in years, an endorsement of his 18-month-old peace talks to end the Western Hemisphere’s longest-running conflict.

Santos got 53 percent of the votes for candidates, against 47 percent for right-wing challenger Oscar Ivan Zuluaga, the hand-picked candidate of former two-term President Alvaro Uribe, whom many considered the true challenger. More than 600,000 voters cast “blank” ballots, a protest vote for neither candidate.

Santos said the win affirmed his claim to be ably steering Colombia through a historic moment — out of a crippling conflict that has claimed more than 200,000 lives, mostly civilians.

“This is the end of more than 50 years of violence in our country and it is the beginning of a Colombia with more justice and social inclusion,” Santos told cheering supporters. ”In four years no one will regret having voted for us.”

He flashed his palm emblazoned with the word “Paz,” or peace — his campaign slogan. Many palms in the crowd were similarly inscribed.