By Brian Ellsworth
CARACAS (Reuters) - Venezuelan opposition supporters vote on Sunday in a primary likely to anoint youthful governor Henrique Capriles as the candidate to face socialist President Hugo Chavez in an October election that is already shaping up as a fierce fight.
Outwitted by Chavez since 1998, opposition leaders hope the nationwide ballot will galvanize their ranks, produce a unity candidate and help them finally unseat Chavez, whose mix of social spending and hostility to business has split the OPEC member nation's people.
Polls show Capriles, 39, an energetic state governor who hails Brazil's market-friendly but socially-conscious policy model as his inspiration, is as much as 20 percentage points ahead of his nearest rival, Zulia state governor Pablo Perez.
Strong voter turnout on Sunday would help give the opposition momentum for a campaign where it hopes to portray Chavez, 57, as a Cold War-era ideologue who has lost focus on day-to-day problems such as crime and unemployment.
"I'm not an imperialist. Those are debates from 50 years ago when I wasn't even born," Miranda state governor Capriles recently told reporters, referring to Chavez's epithet for foes.
"This is a debate between stagnation and progress."
Drawing derision from Chavez, the five candidates in the primary have crisscrossed Venezuela, from Andean foothills to Amazon jungle hamlets, attacking his record and promising to stay united behind whoever wins on Sunday.
While most have avoided confrontation with Chavez and instead stressed concern over crime and jobs, the only female candidate, right-wing independent Maria Corina Machado, has added spice with a torrent of vitriol against the president.
Mocked as "that little bourgeois woman" by the president, she jumped to third in the polls after a highly-publicized exchange in Congress during a 9 1/2-hour Chavez speech where she likened his nationalizations to theft.
The vote for the Democratic Unity coalition's candidate will help turn the page on a decade of internecine disputes among the opposition. Efforts to push Chavez out by force through street protests, a bungled coup and a crippling oil strike all failed.
"The primaries have revealed a much more mature and better organized opposition," wrote Barclays Capital, one of numerous Wall Street outfits closely tracking the opposition vote for its impact on bond prices and the likelihood of government change.
Remaining united will be essential for the opposition if they are to mount a serious challenge.
If they win power, they would face a mammoth task reversing Chavez's "21st century revolution".
They have pledged to move slowly on overturning some of his flagship policies like nationalizations and currency controls so as not to cause economic chaos. But they would likely move quicker on shunning allies like Iran, Belarus and Cuba.
Coalition leaders say a turnout of 2 million voters on Sunday would be a huge success.
Ruling party officials, though, are already gleefully pointing out that it would be a fraction of Venezuela's 18 million registered voters and thus a sign of weakness.
"They're an utterly retrograde and mediocre group," Chavez chuckled at last weekend's celebration of his 13 years in power.
Polls, however, show Venezuela deeply split with at least a third of voters leaning clearly towards the opposition and many undecided, even if Chavez appears to have the edge.
Pollsters say his lead may diminish once the opposition has rallied behind a single candidate.
The October vote will be one of the biggest tests to date for Latin America's most prominent leftist leader, who has become a flagbearer for anti-U.S. sentiment around the world.
Though he appears to have recovered from an undisclosed type of cancer diagnosed last year, problems ranging from blackouts to shortages of groceries have offset his overwhelming charisma and plethora of oil-financed social programs.
Chavez in recent months has unveiled new social programs that provide direct cash payments to poor mothers and senior citizens while stepping up home construction in what opposition leaders call a cynical use of state funds for electoral ends.
Chavez's much-vaunted "missions" - providing benefits from subsidized food to free medical care and housing - have been a mainstay of his popularity.
(Additional reporting by Andrew Cawthorne and Diego Ore; Editing by Andrew Cawthorne and Kieran Murray)