By Alexandra Alper
SAN JOSE, Costa Rica (Reuters) - A centre-left academic who has never held elected office easily won Costa Rica's presidential election on Sunday, ousting the graft-stained ruling party from power after its candidate quit campaigning a month ago.
Former diplomat Luis Guillermo Solis, of the Citizen Action Party (PAC), won with around 78 percent of votes by tapping in to public anger at rising inequality and government corruption scandals.
His win dislodges a two-party dynasty that has governed the coffee-producing country for decades. It is also another victory for Latin America's centre-left parties, which have steadily gained ground across the region in recent years.
"More than 1 million Costa Ricans have said yes to change," Solis told thousands of cheering supporters waving red-and-yellow party flags on Sunday night. "We need to shift away from ... a violence expressed in poverty, in inequality and in the utterly perverse form of corruption."
Solis was a relative unknown just a few months ago but he defied pollsters' predictions by coming in ahead of his rivals in a first round of voting in February, and then took a huge lead in opinion polls ahead of the run-off.
In a bizarre twist, his rival Johnny Araya of the ruling National Liberation Party (PLN) announced last month he was halting his campaign as polls showed him with little or no chance of catching Solis.
Araya remained on the ballot as required by the constitution and his party continued to campaign, but a heavy defeat looked inevitable.
Solis had 77.88 percent of the vote with returns in from 94 percent of polling booths, Costa Rica's election tribunal said. Araya had just 22.12 percent of the vote, and quickly conceded defeat.
A published author well versed in international relations and global trade, Solis ran on a promise to fight Costa Rica's stubborn poverty rate and to stamp out corruption, an issue that has dogged incumbent President Laura Chinchilla's administration and which struck a chord with voters.
"It's been four years of daily suffering," said Mercedes Castillo, a 66-year-old housewife and mother-of-three, after voting for Solis at a high school in the capital, San Jose. "There's just too much corruption."
Jubilant Solis supporters thronged in the streets of San Jose, and drivers honked their horns in celebration.
Solis' victory hands the young PAC its first presidential victory, and wrests power from the PLN, which has been in power since 2006.
Solis was a member of the PLN for 30 years, but abandoned the party in 2005, denouncing internal voting irregularities.
A prosecutor's investigation into allegations of abuse of authority and embezzlement while Araya was mayor of San Jose made it hard for the former front-runner to distance himself from party scandals.
"There is a desire for a real change and I think Solis was able to embody that," said Michael Shifter, president of the Inter-American Dialogue think tank. "It is shaking up the traditional political establishment in Costa Rica."
Hailing from a family of shoemakers, Solis was born in San Jose in 1958 and traces his roots to Chinese-Jamaicans who migrated to Costa Rica in the early 1900s.
He earned a masters degree at the University of Tulane before becoming an academic and diplomat.
He has promised to boost social spending, although he says he will wait two years before raising taxes.
His more egalitarian message chimed with voters, who have seen inequality rise steadily in recent years.
"We want to recover that sense of solidarity, of social inclusion, and commitment to the neediest Costa Ricans that has been lost," the 55-year-old told a news conference on Saturday.
He faces an uphill battle in a National Assembly where his party will have only 13 of 57 seats, although analysts tout his ability to reach across the aisle thanks to his ties to the PLN.
He must also square rising government debt with a campaign promise not to raise taxes for two years, despite pledges to boost spending on education.
"He's going to have a government without money, a fiscal deficit of 6 percent, and lots of social spending commitments," said Jose Carlos Chinchilla, a political analyst and a director at the University of Costa Rica.
Solis has also said he hopes to attract new businesses to Costa Rica's booming free-trade zones, which have enticed the likes of Hewlett-Packard Co.
(Additional reporting by Zach Dyer; Writing by Simon Gardner and Gabriel Stargardter; Editing by Kieran Murray)