By Alexandra Ulmer and Alexandra Valencia
QUITO (Reuters) - An ally of leftist President Rafael Correa and a right-wing former bank boss are battling to become Ecuador's next president in Sunday's election after a tense and tight campaign in the historically volatile Andean nation.
With a sputtering economy the top voter concern, Ecuadoreans will chose between continuing a decade of leftist rule or following several South American nations in shifting toward a more pro-business government as a commodities boom ends.
Lenin Moreno, 64, a paraplegic former vice-president, just missed the minimum threshold to win the presidency in the first round in February, and latest polls show him narrowly beating conservative rival Guillermo Lasso this time around.
Moreno, who uses a wheelchair since being shot during a robbery in 1998, has promised to boost social benefits to single mothers, pensioners and disabled Ecuadoreans.
He paints his opponent as an elitist who would slash welfare policies and links him to a 1999 financial crisis when hundreds of thousands of Ecuadoreans lost their savings.
"We've come so far. Now we're going to improve further," Moreno told crowds at a recent rally in Ecuador's sweltering coastal region.
"Say no the banker!" he also said of Lasso, whom foes accuse of using shady offshore holdings to dodge taxes. "(He) wants to submit Ecuadoreans to instability and permanent conflict."
Lasso, a 61-year-old former head of Banco de Guayaquil who has campaigned on boosting jobs, retorts Moreno is recklessly over-promising considering Ecuador's highly indebted economy.
He also accuses the ruling Country Alliance party of covering up corruption scandals, stifling media, and stacking institutions with their supporters.
"Say no to those who want to turn us into Venezuela!" Lasso told hundreds of cheering supporters during his closing speech in a low-income part of Quito on Wednesday, alluding to food shortages and spiraling inflation under Venezuelan President Nicolas Maduro, a Correa ally.
In addition to vowing a tough line against Maduro, Lasso has also promised to remove Wikileaks founder Julian Assange from the Ecuadorean embassy in London.
Polls show Moreno has pulled ahead of Lasso in the last weeks. He had 52.4 percent of valid votes versus Lasso's 47.6 percent in a 18-21 March survey by leading pollster Cedatos with a margin of error of 3.4 percentage points and some 16 percent of voters still undecided.
For a factbox on the candidates, please see:
ECUADOR ON EDGE
With both camps urging supporters to take to the streets to guard against possible fraud, the nation of 16 million is bracing for protests after a decade of relative stability.
Three of eight presidents were toppled in the decade before Correa came to power in 2007. While Correa brought calm to the smallest member of OPEC, opponents accuse him of morphing into an autocrat.
Hundreds of suspicious Lasso supporters massed in front of the electoral council after results were slow to trickle out in February's first round. And Lasso accused government-paid thugs of trying to attack him with rocks, sticks, and knives after a soccer game on Tuesday. The government rejected the accusation.
Should Lasso win, he could also face trouble governing, as the ruling leftist party has a majority in Congress.
"Opposition to his policies will be relatively high right off the bat," Eurasia analyst Risa Grais-Targow in a note to clients.
"Lasso would try to move quickly toward more orthodox macroeconomic policies aimed at attracting foreign direct investment, including a reduction in corporate taxes, eliminating the tax on capital outflows, eliminating emergency tariffs, and engaging with the IMF and other multi-laterals."
While Moreno, a soft-spoken former U.N. envoy on disability, has a more moderate style than Correa, observers question how much autonomy he will have. Steep debts - Ecuador owes oil service company Schlumberger around $1.1 billion - and uncertainty over how he will finance his raft of promised benefits could also lead to early trouble.
Either way, both presidents will have to wrestle with strong voter demand for jobs.
"Even when we go out to look for work, we can't find any," said construction worker Marco Manotoa, 23, who has been unemployed for three months and plans to vote Lasso. "The country needs change."
The new president will take office on May 24 for a four-year term.
(Writing by Alexandra Ulmer; Editing by Andrew Cawthorne and Alistair Bell)