By Danny Ramos and Mitra Taj
LA PAZ (Reuters) - Bolivia will go to the polls on Sunday in an era-defining vote either to cement Evo Morales in power for a controversial fourth term or to dislodge the iconic left-wing leader, who has ruled the land-locked South American country for nearly 14 years.
Morales, who swept into power in 2006 pledging to bolster Bolivia's marginalized indigenous groups, is leading in opinion polls ahead of the Oct. 20 vote. But his main rival Carlos Mesa has been closing the gap.
The election - expected to be the toughest challenge to Morales' rule yet - has sparked debate about President "Evo" as he is often known. Solid economic growth has made him a poster boy for socialism, but his defiance of term limits has sparked angry street protests, with some calling him a "dictator".
"Being in power for over a decade is now starting to wear on President Evo Morales' government and its legitimacy," said Marcelo Arequipa, a political science professor in Bolivia. "This is going to be a very complex election."
Pollsters expect Morales to win the first round, but not an outright victory - a scenario which would lead to a second round run-off in December.
Morales, who won the previous two elections with more than 60% of the vote, faces a bigger battle this time, with popular anger over term-limits also fed in recent weeks by what critics called a slow government response to devastating forest fires.
The 59-year-old indigenous president needs to receive at least 40% of the vote and have a 10-point lead over the second-place contender to avoid a second round, which some polls suggest he could even lose.
Some among the country's indigenous population, which numbers more than 4 million people, feel Morales has lost touch with the people, even among his own tribe the Aymara.
The election will also see the country's 166-seat two-house Congress be renewed for the period 2020-2025. Other presidential candidates include Oscar Ortiz's anti-Evo "Bolivia Says No" party and Chi Hyun Chung of the Christian Democratic party.
EVO MORALES
Morales has been in continuous power for longer than any other standing leader in Latin America, one of a wave of left-wing leaders who dominated the continent's politics at the start of the century.
The former llama herder and coca leaf farmer - now more often seen in colorfully-embroidered alpaca suits - took office as the first indigenous leader of the farming and gas-driven economy, one of the region's smallest.
The head of the country's Movement for Socialism party, he was reelected in 2009 and 2014. If he wins this year he would extend his time in office to 19 years.
The fact he's running at all is a thorny question. His own 2009 constitution set a limit of two five-year terms, and in 2016 Bolivians voted in a referendum against him running again this year. Morales convinced the country's Constitutional Court to let him stand anyway, saying term limits violated his "human rights".
Morales' critics say he is straining the country's democratic system to stay in power, alleging the president and his allies use strong-arm tactics against those who oppose them.
Morales and his supporters point to steady economic growth and falling poverty levels under his leadership, and say his nationalization of key industries protects Bolivia's interests.
"I want to tell you all that in these elections we'll once again beat those who sell out the homeland, we'll beat out the neoliberals," Morales said at an election rally this week.
CARLOS MESA
His rival Mesa, a writer, historian and journalist, was president of Bolivia between October 2003 and June 2005, a period of social upheaval that forced him to resign. Morales, then the head of a union, was one of the protest leaders.
Mesa, 66, now wants a second chance to lead the country as the head of the Citizen Community (CC) alliance.
The white haired and bespectacled leader has looked to soften his image, saying he would not represent a neo-liberal shift, nor push privatization of industries key to Bolivia's economy, including gas and a nascent lithium sector.
He faces the challenge of unifying Bolivians amid a split field, as well as escaping the shadow of his ill-fated earlier administration. Critics say he lacks decisiveness.
But at election rallies, Mesa has decried the "dictatorial" shift under Morales, and sought to win over voters by saying he is the only candidate who can pose a serious challenge.