By John Whitesides
WASHINGTON (Reuters) - If the Republican presidential race becomes a two-man fight between Mitt Romney and Rick Perry -- and judging from Wednesday's debate it already is -- primary voters will have a stark choice.
East Coast establishment calm versus Texas Tea Party fire. Private sector business background versus lifelong politician. Mormon versus evangelical Christian.
Romney, the one-time moderate from liberal Massachusetts, and Perry, the outspoken conservative from the west Texas plains, share little except party membership, good hair and a past as governors of their respective states.
"On a personal level, these guys are different in every possible way," said Dan Schnur, an aide on Republican John McCain's 2000 presidential campaign who teaches at the University of Southern California. "You couldn't have a sharper choice."
The contrast in styles was in full display at the California debate, where the Romney-Perry rivalry turned the other six candidates on stage into bit players except for occasional signs of life from Jon Huntsman.
Perry was a fountain of red-meat conservative rhetoric. He declared the Social Security retirement plan a "Ponzi scheme" and a "monstrous lie," and said President Barack Obama had bad information or was an "abject liar" if he believed the border with Mexico was safer.
Romney was the voice of moderation. He said Social Security should be overhauled but not dismantled, called Obama "a nice guy" and sympathized with Perry when he admitted he made a mistake in ordering young girls be vaccinated for a sexually transmitted virus that causes cervical cancer.
Perry's fiery style is aimed directly at the Tea Party fiscal and social conservatives who play a big role in the nominating process, but could turn off independents and conservative Democrats who often decide the general election.
Romney, whose moderate past and Obama-like healthcare plan in Massachusetts have made him an object of suspicion for some conservatives, has largely targeted his pitch to independents and swing voters who could decide a general election.
The outcome of their Republican battle for the right to challenge Obama in 2012 could set the party's course for years to come, determining if it continues its drift to the right or begins to shift back to the middle.
CONFLICT ON JOBS
The two candidates have relatively few policy differences, but clashed again at the debate on who would be better at creating jobs. Romney touts his private business experience at an equity firm, while Perry points to his record as governor in Texas.
But the difference in rhetoric on Social Security could become a flashpoint in the campaign. Perry's fervent attacks on a program that is extremely popular with seniors, the demographic group that most frequently votes, worry some Republican strategists.
"You can't win a national campaign when you are on the record calling for the dismantling of Social Security," Steve Schmidt, who headed McCain's 2008 campaign, said on MSNBC.
"It's very problematic for him, and I think it's something that Democrats have a lot of glee over," he said.
The attacks on Social Security might not hurt Perry in a primary race dominated by Tea Party conservatives demanding drastic cuts in government spending, but it could raise concerns about Perry's chances of beating Obama.
"The people who loved Perry are going to love him more," Bruce Buchanan, a political scientist at the University of Texas, said of his debate rhetoric. "The people worried about his electability are going to be more deeply worried than they were before."
Romney was the one-time leader in polls of the 2012 race, but since joining the campaign last month Perry has zoomed past him with the help of deep support from social and religious conservatives.
That has forced Romney to calibrate his approach, appearing at his first Tea Party rally on Sunday and at a conservative forum in South Carolina on Monday in a more blatant appeal to the party's conservative wing.
Ultimately, the winner in the Perry-Romney battle might be the candidate who is most effective in broadening his message and becoming more like the other.
"Does Romney win over the Tea Party and become more of a fighter? Does Perry become calmer and more reasoned? The one who does that best probably wins," Schnur said.
With Perry taking away much of her conservative support, U.S. Representative Michele Bachmann has been sliding in the polls and made little impression on Wednesday.
But Huntsman, the former governor of Utah, had a better and more forceful performance than in the last debate. His showing raised the prospect he could replace Bachmann as the third contender waiting to jump in if either Perry or Romney falter.
"I think Huntsman will be a factor before this is over," said Fergus Cullen, the former chairman of the New Hampshire Republican Party. "If Bachmann is fading and is being eclipsed by Perry, somebody is moving into that third slot."
(Editing by Jackie Frank)