Supporters of Andres Manuel Lopez Obrador, former presidential candidate of the Democratic Revolution Party (PRD), one of them wearing a Mexican Revolution costume, listen his speech at Mexico City's main plaza, the Zocalo, Sunday, Sept. 9, 2012. Lopez Obrador, who led Mexico's main leftist party in the past two presidential elections announced Sunday he is leaving it behind and may start a new party, throwing uncertainty over the future of the nation's political left. (AP Photo/Christian Palma)
