Perry announces presidential aims as Iowa holds poll
Texas Governor Rick Perry has announced his candidacy for the Republican nomination in the 2012 presidential race.
His announcement at a South Carolina event comes as fellow candidates face their first key test of grassroots party opinion in an Iowa straw poll.
The poll is not an official primary but winning is considered a major boost.
The front-runner in national opinion polls, ex-Massachusetts Governor Mitt Romney, is not actively taking part.
Mr Romney is expected to face a strong challenge from the conservative Mr Perry, who succeeded George W Bush as Texas governor.
The strong-jawed Mr Perry told voters in a conference call from Columbia, South Carolina, that he wanted to take on President Barack Obama next year.
"I full-well believe I'm going to win," he said.
In a speech to supporters, he slammed the Obama administration, saying the US "cannot afford four more years of this rudderless leadership".
The BBC's Rajesh Mirchandani in Washington says Mr Perry is a fiscal conservative who has a track record of creating jobs and reducing the role of government.
He is religious with socially conservative views and could be the candidate to unite moderate and right-wing "Tea Party" Republicans, our correspondent adds.
The first official Iowa primaries in the race for the White House are still several months away but the non-binding results of Saturday's straw poll in Ames, Iowa may play an important role in shaping which Republican will take on Barack Obama.
The poll is essentially a state Republican fund-raiser and turnout in the past has ranged from 14,000 to 23,000.
With Mr Romney absent from the straw poll ballot, analysts say the key battle may be between Tim Pawlenty and Michele Bachmann, who are vying for the social conservative vote.
They clashed in Iowa on Thursday night in the third televised debate of the 2012 Republican race.
Mr Pawlenty repeatedly criticised Ms Bachmann's lack of substantive success in enacting a legislative agenda, and accused her of "making false statements".
Ms Bachmann hit back, accusing Mr Pawlenty of pursuing policies that sound "a lot more like Barack Obama".
Mr Pawlenty has been struggling in national opinion polls and may need a strong showing in Iowa.
The other four candidates who have paid to take part in the straw poll are representatives Thaddeus McCotter and Ron Paul, former Pennsylvania Senator Rick Santorum and businessman Herman Cain.
Mr Romney, Utah Governor Jon Huntsman and former House of Representatives Speaker Newt Gingrich have not paid to take part but are still on the ballot list.
The straw poll often sifts out failing candidates but is no guarantee of success. Mr Romney won in 2007 but Mike Huckabee came second and later won the Iowa caucus. John McCain did not take part and won the nomination.
This year's straw poll is almost as noticeable for its absentees - Mr Perry and Sarah Palin, who has yet to decide on her candidacy.
Mrs Palin, who visited the Iowa state fair on Friday, was lukewarm about the importance of the straw poll.
"It's not always the tell-tale sign of what the electorate is feeling. It's who happens to show up and has the time and energy to spend that day for their particular candidate," she said.