Caracas, Venezuela ? Candidates who will oppose Hugo Chavez in Venezuela’s December presidential election have decided to participate in a winner-take-all primary Aug. 13 to decide on a single candidate whom they all promise to support.

It is a measure of the opposition’s weakness that politicians from the nine disparate parties decided on the joint primary in a bid to galvanize an opposition that has largely given up hope of defeating Chavez.

Major opposition parties boycotted last December’s congressional elections after alleging that Chavez had rigged the system. Chavez supporters countered that the opposition was merely acknowledging the likelihood it would lose.

Polls indicate that Manuel Rosales, governor of oil-rich Zulia state, and Julio Borges, a former assemblyman and TV show host, are the leading opposition figures, but both still trail Chavez by a wide margin.