Rick Perry withdraws bid for White House
Rick Perry: "I know when it's time to make a strategic retreat"
The Republican presidential race has been dramatically shaken up after Texas Governor Rick Perry quit and endorsed former House Speaker Newt Gingrich.
His exit came as it emerged front-runner Mitt Romney had not won Iowa's caucuses, as initially thought, because of a mix-up on the vote count.
A resurgent Newt Gingrich, meanwhile, faces embarrassment after his ex-wife claimed he wanted an open marriage.
The four remaining contenders face a crunch TV debate on Thursday.
They are former Massachusetts Governor Mitt Romney, former House of Representatives Speaker Mr Gingrich, veteran Texas Congressman Ron Paul and Christian conservative Rick Santorum.
Mr Romney is the front-runner in the state-by-state race for the Republican Party's nomination to challenge Democratic President Barack Obama for the White House this November.
When Mr Perry entered the race in August, he briefly shot to the front of the pack before gaffes and poor debate performances set him back.
Perry: Where did it all go wrong?
- 1 Oct: Raises eyebrows after saying he would consider sending US troops into Mexico to fight drug war
- 28 Oct: An unusually animated speech by Perry in New Hampshire prompts him to deny speculation he was drunk or on medication
- 10 Nov: In a debate, Mr Perry cannot remember the name of a third government department he would eliminate if elected
- 29 Nov: Mistakenly refers to the minimum voting age as 21 (it's 18)
- 6 Dec: Is fiercely criticised for a campaign ad attacking gays in the military and claiming children can't celebrate Christmas
- 8 Dec: Corrects himself after saying US had been at war with Iran, rather than Iraq
- 9 Dec: Says eight justices sit on the Supreme Court (the number is nine)
- 3 Jan: Reconsiders his campaign after flopping in Iowa, only to change his mind, distributing a photo of himself in athletic attire, giving a thumb-up
- 11 Jan: Attacks Romney as a "vulture" capitalist, provoking conservative outcry that he should not criticise the free-market system
- 16 Jan: His remark in a TV debate that Turkey is ruled by "Islamic terrorists" is seen as yet another gaffe
The Texas governor told media on Thursday: "I've come to the conclusion that there is no viable path forward for me in this 2012 campaign.
"Therefore today I am suspending my campaign and endorsing Newt Gingrich."
Mr Perry said Mr Gingrich was a "conservative visionary", adding: "Newt is not perfect, but who among us is?"
Recent opinion polls have shown Mr Gingrich trimming Mr Romney's lead.
However, Mr Gingrich's ex-wife, Marianne, has made potentially damaging claims in a TV interview to be broadcast in full on Thursday evening by ABC News.
In an excerpt of her remarks on the Nightline programme, the former Mrs Gingrich says her ex-husband wanted an open marriage.
After finishing fifth in Iowa's first-in-the-nation nominating contest, Mr Perry briefly reconsidered his campaign before ploughing on.
He skipped the moderate New England state of New Hampshire to focus on South Carolina. But his message failed to take off even in that conservative southern state.
His departure follows on the heels of former Utah Governor Jon Huntsman, Minnesota Congresswoman Michele Bachmann and last month, Georgia businessman Herman Cain.
Mr Perry had faced calls in recent days to stand aside as rivals warned the conservative vote would fracture across the candidates, ultimately benefiting Mr Romney.
Mr Romney's Mormon faith and political record as governor of the moderate state of Massachusetts is viewed with suspicion by some conservative Republicans.
Also on Thursday, the final results of the Iowa caucuses were certified as a split decision between Mr Romney and Mr Santorum, a former Pennsylvania senator, because of missing data.
Mr Romney had initially been declared the winner of the 3 January nominating contest by eight votes.
But the final count shows Mr Santorum ahead by 34 votes, although no winner has been declared because the results from eight precincts are missing.
According to the certified vote totals, Mr Santorum won 29,839 votes while Mr Romney had 29,805. Mr Paul kept his third-place finish, with 26,036 ballots.
Iowa Republican Party chairman Matt Strawn announced the results at a news conference on Thursday morning.
The Romney campaign called the outcome a "virtual tie", while the Santorum campaign said it changed the narrative of the race.
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