Mexicans will choose their president on Sunday, in a poll dominated by the country's two main conservative parties.
In this largely Catholic nation, leftist politics has remained largely on the margins. This year's opinion polls, however, show that Andres Manuel Lopez Obrador, the main candidate from the left, represents a serious challenge for the presidency.
In a country where nearly half of the people live in poverty, Obrador is promising to end corruption and establish social equality.
Unlike in other Latin American countries -- including Brazil, Argentina, Ecuador and Venezuela -- Mexico's left, however, has struggled to recapture its power base.
Al Jazeera's Franc Contreras reports.