One candidate is a former bishop who casts himself as a Paraguayan David fighting a "monstrous Goliath" in a bid to end 61 years of one-party rule. His rival wants to become the nation's first female president. Polls suggest that Paraguayans could vote out the only ruling party most of them have ever known on Sunday. The Colorado Party has endured through democracy and dictatorship in this poor, agrarian South American nation, and has been in power even longer than Cuba's Communist Party. Hoping to end the party's six-decade run is former Roman Catholic Bishop Fernando Lugo, sometimes called "the bishop of the poor," who several polls show narrowly leading Colorado candidate Blanca Ovelar as well as former army chief Lino Cesar Oviedo ahead of the election. Lugo, 56, then launched a charismatic campaign in which he blamed Paraguay's deep-seated economic woes on decades of corruption by elites who ruled at the expense of the poor in a country of subsistence farmers. "Now is the hour of change! Don't be afraid!" the gray-bearded priest shouted in both Spanish and the Guarani Indian language at a recent rally, at which he quoted from the Bible and wore campesino sandals. Now his Patriotic Alliance for Change is mounting the most serious challenge to the Colorado Party since democratic elections returned after the country's 35-year military dictatorship ended in 1989.