The result was a stunning turnaround for Abbott, a 55-year-old former Roman Catholic seminarian and Rhodes scholar who has never been particularly popular and was once dubbed unelectable by opponents and some of his own supporters.
He emerged victorious thanks, in large part, to the frustration of a country fed up with Labor and its once-popular leader, Kevin Rudd, who had engaged in a years-long power struggle with his former deputy, Julia Gillard. Gillard, who became the nation's first female prime minister after ousting Rudd in a party vote in 2010, ended up losing her job to Rudd three years later in a similar internal party coup.
"I now look forward to forming a government that is competent, that is trustworthy and which purposefully and steadfastly and methodically sets about delivering on our commitments to you the Australian people," Abbott told supporters in his victory speech Saturday night.
With more than 90 percent of votes counted, official figures from the Australian Electoral Commission showed the Liberals ahead 53 percent to Labor's 47 percent. The coalition was on track to win 91 seats in the 150-seat House of Representatives, and Labor 54.
For a range of reasons, Abbott has been dismissed by many critics as not being prime minister material. A supremely fit volunteer lifeguard, he is often parodied in the media for wearing the red-and-yellow cap and brief swimwear worn by Australian lifeguards.
He has joked that he was not allowed to wear swim briefs, known in Australia as "budgie smugglers" — a reference to the budgerigar, a small Australian parrot — during the five-week election campaign.
Abbott's approval ratings recently improved in polls, but he remains relatively unpopular, particularly among women voters.
"All those ridiculous people who said he was unelectable should understand how foolish they were to underestimate him," former conservative Prime Minister John Howard, who promoted Abbott to his Cabinet during an 11-year reign, told Seven Network television Saturday.
Abbott was regarded as a competent minister. But his aggressive politics, social conservatism and knack for igniting controversy raised questions about his suitability as a potential national leader. He was elected party leader by his Liberal Party colleagues in late 2009 by a single vote majority.
His coalition was narrowly defeated in 2010 elections following a campaign in which Abbott made some conspicuous deviations from policy.
He came under fire during the campaign over an interview in which he drew a distinction between what he sometimes says "in the heat of discussion" and "an absolutely calm, considered, prepared, scripted remark."
In the latest campaign, he was criticized for listing a female candidate's "sex appeal" as a political asset, then defending himself by calling it a "charming compliment." In another incident, he accidentally drew laughter during a speech by saying that no one is the "suppository" of all wisdom, when he apparently meant to say "repository."
But the drama between Rudd and Gillard, combined with Labor reneging on an election promise by imposing a deeply unpopular tax on the nation's biggest carbon polluters, proved deadly for Labor's re-election chances.
Abbott, who becomes Australia's third prime minister in three months, will likely end a period of extraordinary political instability and apparent chaos in Australia.
The voter swing away from Labor was a resounding rejection of Australia's first minority government since World War II. Voters disliked the deals and compromises struck between Labor, the minor Greens party and independent lawmakers to keep their fragile, disparate and sometime chaotic coalition together for the past three years, including the carbon tax.
Abbott has vowed to scrap the carbon tax from July 2014 — two years after it was implemented — and instead introduce taxpayer-funded incentives for polluters to operate cleaner.
It is unclear whether Abbott will be able to pass the necessary law changes through Parliament, but he has threatened to call early elections if the Senate thwarts him.
Australia's new leader inherits a slowing economy, hurt by the cooling of a mining boom that kept the resource-rich nation out of recession during the global financial crisis.
Abbott has promised to slash foreign aid spending as he concentrates on returning the budget to surplus. Labor spent billions of dollars on economic stimulus projects to avoid recession. But declining corporate tax revenues from a slowdown in mining forced Labor to break a promise to return the budget to surplus in the last fiscal year.
Abbott has also promised to repeal a tax on coal and iron ore mining companies, which he blames in part for the downturn in the mining boom. The 30 percent tax on the profits of iron ore and coal miners was designed to cash in on burgeoning profits from a mineral boom fueled by Chinese industrial demand. But the boom was easing before the tax took effect. The tax was initially forecast to earn the government 3 billion Australian dollars ($2.7 billion) in its first year, but brought in only AU$126 million after six months.
Saturday's election likely brought Australia's first Aboriginal woman to Parliament. Former Olympian Nova Peris is almost certain to win a Senate seat for Labor in the Northern Territory, but the final results will not be known for days. Less likely is WikiLeaks founder Julian Assange's bid for a Senate seat in Victoria state.
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