ison and cleared of a coup-plotting conviction, has formalized his presidential nomination under an opposition party. Oviedo, a populist with support among Paraguay's poor Indian majority, was the only contender on the primary ballot for his National Union of Ethical Citizens, an opposition party he founded in 2000.
The April 20 presidential election will decide who succeeds President Nicanor Duarte, whose five-year term ends in August.
Another major opposition candidate, former Catholic bishop Fernando Lugo, launched his campaign in 2007 with the Patriotic Alliance for Change - a coalition of leftist, labor, peasant and Indian groups.
The field is still missing the ruling party nominee.
A female former education minister, Blanca Ovelar, is fighting a bitter Colorado primary battle against a former vice president, Luis Castiglioni. The Dec. 16 primary was so close that a slow ballot-by-ballot recount is being conducted as both insist they will prevail.
Oviedo and Lugo have vowed to campaign to end 60 years of one-party rule by the Colorado party. Analysts say the emergence of two major opposition candidates could split the opposition vote, favoring the ruling party.
Oviedo, a former army general, served half a 10-year sentence before his release. In October the Supreme Court exonerated him in a plot to overthrow President Juan Carlos Wasmosy in a short-lived rebellion in April 1996.
