Uribe returns to office in Colombia

Colombia’s former President Alvaro Uribe is back in elected office, this time in the Senate, which could potentially complicate efforts by the government to make peace with leftist rebels because his new party opposes peace talks aimed at ending five decades of civil conflict.

Election results also consolidated President Juan Manuel Santos as front-runner in a presidential vote set for May 25 but reduces the majority he will rely on if re-elected, for legislative support to implement a peace deal with the Revolutionary Armed Forces of Colombia, or FARC rebels, if talks succeed.

Santos is seeking a second term so he can complete negotiations with the FARC that could end a war that has killed around 220,000 and displaced millions, and transform Colombia's political landscape if the rebels' gain the political participation they seek.

Uribe is a fierce critic of the Santos government who believes the FARC should instead be beaten with military force.

His party will likely seek to obstruct legislation if a peace deal is reached that would enable FARC rebels to enter the political system without serving considerable jail time.

With 95 percent of votes counted, 62-year-old Santos' center-right U Party emerged the single biggest party in both Congressional houses with 15 percent of the vote for each.

Including votes for coalition parties including the Conservative, Liberal, Green, Radical Change and U parties, the alliance held on to a majority of the 166 seats in the lower house and 102 in the Senate.

The coalition's fate will depend on the Conservatives, who are expected to win 17 seats. But it isn't clear if the Conservatives will stay with Santos or join Uribe, who as president in 2002-10 seriously weakened the FARC with close U.S. intelligence and logistical assistance. Santos was defense minister in 2006-09.

If the Conservatives choose Uribe's camp, he could seek to erect legislative obstacles to any peace deal.

Uribe's new Centro Democratico party took almost 15 percent of votes in the Senate where the ex-president will take up a seat marking his return to political office after his mandate ended in 2010. The party won just under 10 percent of votes for the lower house.

The government’s secretive peace talks reached a partial accord late last year on the FARC's participation in politics, a highly controversial item on the five-point agenda. Any deal with the rebels would be put to the nation in a referendum, and then to congress to devise laws for its implementation.

Despite slow but encouraging progress at the negotiations in Cuba's capital Havana that began in late 2012, the decision to engage in peace talks with the guerrillas remains divisive among Colombians and will be pivotal in voters' choice of president in May.

Uribe became the de facto opposition and Santos' fiercest critic shortly after backing him for office in 2010. The acrimony worsened when Santos announced peace talks with the FARC, seen as a terrorist group by the United Sates and the European Union.

"I'm afraid of what will happen if an impunity pact is signed with terrorist leaders," Uribe said at the close of his campaign. "When crime is a champion, there's no condition in the heart to forgive the criminal. The lack of justice may lead to peace accords in Havana but more violence in Colombia."

Colombia, a recipient of hundreds of million of dollars in annual U.S. anti-narcotics aid, has fought the FARC, right-wing paramilitaries and a smaller rebel group, the ELN, since 1964.

Santos is expected to reveal soon that the ELN will also start peace talks with his government, which is likely to give a further boost to his chances of securing another term.

Al Jazeera and wire services