Colombian opposition party Polo Democratic Alternative (PDA) will this weekend choose its candidate to fight the 2014 presidential elections against an almost certain to run for re-election President Juan Manuel Santos.

The PDA´s national congress, the third of its kind, begins tomorrow and under discussion is not only party policy, but also who will lead the group into the forthcoming elections. Two big names are expected to go forward as possible candidates, Jorge Enrique Robledo, and Clara López.

Robledo has the star appeal; his polemic and permanent campaigning style make him a hero for many on the left. Colombia Politics profiled this senator last month and has long tipped him has a potential presidential candidate.

In 2010, Robledo became the second most voted for senator, behind the U Party´s Juan Lozano. He is one of the most visible senators and has been a fierce critic of the neo-liberalism of the Uribe and Santos regimes. In a poll of influential thought leaders released today, Robledo was labelled the best performing senator.

Whether you agree with his politics or not, Robledo is the undisputed opposition heavy weight in Congress. His campaigns have been as diverse as they have been full-bloodedly fought. Last year he became the darling of the student movement, attacking the Santos administration´s education reform bill (which was eventually ditched because of the level and organization of opposition). This year he has taken on the implementation of the land restitution law, stood as the loudest voice against the free trade agreement with the USA, and has lampooning the government´s tax reform legislation currently before lawmakers.

Clara López is less polemic and less obviously a campaigning figure. The current director of the PDA party, López won credit for her work as the caretaker Mayor of Bogotá last year. López stepped in following the deposition of Samuel Moreno (who faced corruption charges) and was widely recognized as a successful administrator, in stark contrast to current Mayor and former Polo presidential candidate, Gustavo Petro.

This website has previously argued that Clara López represents the PDA´s best electoral hope.  For us, López´s measured style and her greater appeal to those closer to the political centre, means she has a higher chance of gathering in votes from a wider cross-section of society. It is difficult to see how Robledo would appeal (electorally speaking) to anyone other than a committed socialist. Fine if the PDA are content to languish in the polls.

López is without doubt a left-winger, but she scares away fewer voters than does Robledo. Colombia is not a left-wing country, but some 30% of the electorate is said to be prepared to vote for a candidate of this colour. Were López able to present a more centrist platform then this figure could well move north.

The problem for the Colombian left is that it has become fractured and disparate. Petro´s Progressives party and Piedad Córdoba´s far left Marcha Patriotica movement could well split the vote, leaving the PDA with precious little representation in Congress. It has even been predicted that unless the PDA run a successful election campaign they could struggle to return any politicians to the Capitolio in 2014.

The Santos administration controls over 90% of Colombia´s Congress leaving the PDA as the only real and organized opposition to the government. A PDA presence in Congress is important for the health of the nation´s democracy.

Despite disastrous regional elections last year, and a series of high-profile departures and splits since the last congressional elections in 2010, the PDA, with the right candidate will try to position itself as only viable alternative to the centre centre-right politics of the status quo.

Will the PDA choose wisely?