Voting begins on Tuesday in Sri Lanka's first post-war presidential election, contested by the men who ended the island nation's 37-year conflict but whose bitter clash threatens more instability.
Last May, President Mahinda Rajapakse and his army chief Sarath Fonseka wiped out Sri Lanka's Tamil Tiger rebels, who had fought for a Tamil homeland since 1972, in a military campaign since dogged by allegations of war crimes.
But from close allies on the battlefield they have turned into irreconcilable enemies after Fonseka, a 59-year-old political novice, decided to challenge his former boss at the ballot box on an anti-corruption platform.
"Whoever wins the race, the country has already lost," said SL Gunasekera, a political analyst and senior lawyer who also said that weeks of mud-slinging had further damaged the image of the Indian Ocean nation.
In the acrimonious run-up to the vote, the opposition and government have made claim and counter-claim about each other's malevolent intentions, raising tension across the country and the prospect of a contested result.
Fonseka has hardened his rhetoric in recent days, pointing to alleged troop movements, plans to disrupt the media and instructions to the police as evidence that the government will use the army to stay in power if necessary.
"These are the indications of a military coup," he told reporters on Monday in his last pre-poll press conference surrounded by his technicolour coalition of Marxists, Tamils, Muslims and right-wingers.
"If there is a war, we will face it," he added, threatening street protests and rallies.
Rajapakse, like Fonseka a nationalist from the majority Sinhalese ethnic group, has vowed to ensure the poll goes off peacefully and has called on voters to give him a second mandate to develop the country post-war.
His supporters are drawn by the mustachioed 64-year-old's charisma and populist approach and see him as the man who liberated the country from a fight with the Tigers that cost 80,000-100,000 lives, according to the UN.
Rajapakse and Fonseka fell out in the aftermath of the conflict when the army commander was moved to a ceremonial position by the president, who reportedly suspected him of plotting a coup himself.
Their relationship began to sour when Fonseka's horoscope -- astrology is taken extremely seriously in Sri Lanka -- was read by an influential Buddhist monk who saw a future statesman in the career military man.
There are no reliable opinion polls in the country and political observers say the election is too close to call. Both camps believe they can claim a majority in the voting by the 14.08-million-strong electorate.
In a curious twist, the minority Tamils, on whose behalf the Tigers waged their campaign of suicide bombings and assassinations, might swing the final result if the two candidates split the Sinhalese vote equally.
A total of 68,000 police and about 12,000 soldiers are on duty on Tuesday to guard against violence, which has flared on more than 1,000 occasions in the run up to the election, police figures show.
At least four activists have been killed and the house of a key opposition fundraiser was bombed last Friday.
Amid fears that Fonseka and his allies will reject any Rajapakse victory because of fraud, Foreign Minister Rohitha Bogollagama on Monday played down warnings about street protests.
"I don't think the people of Sri Lanka have time for street protests," he said. "It has never happened."
The Centre for Monitoring Election Violence (CMEV), an accredited monitoring body, has already announced serious flaws in the electoral process in the run-up to the race, which includes 22 candidates in total.
"With deep regret we have to say that we have a picture of a dysfunctional electoral process and the breakdown of the authority of the (independent) elections commission," CMEV director Paikiasothy Saravanamuttu said.
Elections Commissioner Dayananda Dissanayake, responsible for announcing the winner on Wednesday, has already criticised public servants for failing to prevent the misuse of state resources for political purposes.
The first results are likely to trickle out late Tuesday, with the final outcome expected to be known on Wednesday. Voting begins at 7:00 am (0130 GMT) and ends at 4:00 pm (1030 GMT).