Republican candidates clash at Iowa debate
Republican presidential candidates traded barbs as they vowed to slash taxes at a televised debate in Iowa.
The eight contenders are jockeying for position in the nomination race, mainly against frontrunner Mitt Romney.
Michele Bachmann and Tim Pawlenty attacked one another, while others touted their experience as governors.
Texas Governor Rick Perry did not join the debate, but stole some of the spotlight when his spokesman said Mr Perry would run for the White House.
The Texas governor is expected to announce his candidacy in South Carolina on Saturday. A spokesman said hours before Thursday night's debate Mr Perry would make his intentions "very clear".
The candidates hope to win the Republican nomination to face President Barack Obama in the November 2012 general election.
Attention now turns to Iowa, where Republican voters on Saturday will cast non-binding "straw poll" ballots.
The results have the power to make or break candidates in the second tier of the field, by highlighting their organisational prowess and grassroots support - or lack thereof.
Mr Romney, Mr Perry and Utah Governor Jon Huntsman will not compete in the straw poll.
Former Alaska Governor and 2008 Republican vice-presidential nominee Sarah Palin, who has flirted with a candidacy but has not entered the race, is to begin a bus tour of Iowa on Friday. She is not participating in the straw poll.
The Republican field has been slow to take shape this year, although the first official balloting in the primary contest will not be held until February in Iowa.
In Iowa on Thursday night, Ms Bachmann, a Minnesota congresswoman; Mr Pawlenty, former Minnesota governor, Mr Huntsman and others faced a key test of their ability to emerge as Mr Romney's chief challenger.
As the third debate of the 2012 race began, hosted by Fox News, the candidates offered a round of boilerplate Republican calls for lower taxes and repeal of Mr Obama's "Obamacare" healthcare reform law of 2010.
Mr Romney, a former financier and Massachusetts governor, touted his experience in the private sector but was forced to defend his record as governor over similarities between his healthcare policy in Massachusetts and Mr Obama's 2010 law.
Mr Huntsman talked up his record as governor of Utah, Mr Pawlenty his record of financial management as Minnesota governor and Ms Bachmann - a Minnesota congresswoman - her opposition to the Democratic legislative agenda.
Congressman Ron Paul, former Senator Rick Santorum, former House Speaker Newt Gingrich and a businessman Herman Cain also took the stage for the wide-ranging debate.
Mr Romney, who failed in his 2008 bid for the Republican nomination, leads the current pack in polling and fundraising.
Much of the early debate centred on exchanges of attacks between Mr Pawlenty and Ms Bachmann, who are vying to pull to the front of the pack and take on Mr Romney.
Mr Pawlenty repeatedly criticised Ms Bachmann's lack of substantive success in enacting a legislative agenda, and accused her of "making false statements".
"She speaks of leading these efforts in Washington and Minnesota," he said. "Leading and failing is not the objective."
'Mickey Mouse questions'
Ms Bachmann hit back, attacking Mr Pawlenty's pursuit of policies that sound "a lot more like Barack Obama".
Later, Mr Santorum - who complained that he was not being given enough time to speak - clashed with Mr Paul over foreign policy and called for a 0% tax on manufacturing.
In addition, pizza restaurant magnate Herman Cain said Islamic "sharia law" should never be recognised in US courts, and on immigration said "America can be a nation of high fences and wide open doors".
Mr Gingrich attacked "Mickey Mouse questions" from the news media on reports of staff defections in his campaign, while Ms Bachmann said Americans should be allowed to purchase whatever lightbulbs they wanted.
Mr Huntsman has thus far failed to live up to the excitement his entrance into the race generated.
In the debate he defended himself over his previous role as Barack Obama's ambassador to China, and said his support for civil unions was a personal choice.
Known as a political moderate, Mr Huntsman has pledged to run a civil campaign.