NEW YORK, Oct 19 (Reuters) It's not enough for US Republican presidential candidates to be conservatives. They've got to be bigger and better conservatives to win the hearts of right-wing America.
As Mitt Romney, Rudy Giuliani, Fred Thompson and John McCain fight for votes, some of the hardest punches are from those accusing one another of being newcomers to lower taxes or opposing abortion.
''The Republicans have had to 'out-conservative' each other,'' said Lee Miringoff, pollster at the Marist Institute for Public Opinion in Poughkeepsie, New York.
That contest heats up this week, when several candidates seeking the Republican Party's nomination in the November 2008 presidential election visit with conservative Christians at a ''Values Voter Summit'' in Washington.
But just being conservative isn't enough, said Doug Muzzio, professor of political affairs at New York's Baruch College.
''It's how conservative are you, and how long have you been conservative?'' Appealing to the right is always a vital strategy for candidates seeking the Republican nomination, but the battle over conservative credentials is particularly sharp in this campaign because several of the top candidates have distinctly liberal-leaning records.
Thompson paraded his credentials this week before New York's small but vocal Conservative Party, recalling his first foray into politics supporting conservative Barry Goldwater in 1964.
''I was a conservative yesterday, I am a conservative today and I will be a conservative tomorrow,'' said the former US senator from Tennessee, known to many Americans for playing a folksy district attorney on NBC's ''Law and Order'' drama.
Former US Sen Al D'Amato, who has locked horns for years with Giuliani on New York's political scene, chimed in to declare he liked Thompson because ''he's not a panderer.'' ''Instead of like some of the leading candidates who will try to be whatever they can to try to get votes, he's consistent,'' D'Amato said.
Giuliani, who backed gun control and immigrant rights as mayor of New York, upsets conservatives with his personal life as well as his politics.
Twice-divorced, Giuliani dated the woman who is his current wife while still married to his former wife and lived with gay friends after leaving the mayor's mansion.
BATTLE OVER RECORDS Romney catches grief for his record as governor of Massachusetts, when he was pro-choice, pro-gay rights and signed near-universal health insurance into law.
''His record is very clear that he ran in Massachusetts as a very liberal Republican,'' said Sen. John McCain on CBS television's ''Face the Nation.'' ''I think that my record is very clear of more than 20 years of being a conservative Republican.
''Isn't consistency on fundamental issues an important factor in this race?'' McCain asked.
The candidates who have been conservative longest need to remind voters that Giuliani and Romney are ''flip-floppers,'' said Muzzio.
''They're not conservatives. If you look at their positions in the not-too-distant past, they were 180 degrees different than they are now,'' said Muzzio. ''These guys are like beached fish, flip-flopping they way they do.'' But critics note Thompson lobbied for a family-planning group that supported abortion rights, and McCain has paid dearly for once calling evangelicals ''agents of intolerance.'' ''All four top-tier candidates have a history which is checkered, at least as far as conservatism goes,'' said Dante Scala, professor of political science at the University of New Hampshire. ''So there's plenty of material to make the argument that, 'Yeah, I'm a conservative,' but also plenty of material to prove the opposite.'' While Republican candidates need right-wing votes to win the nomination, their support has a downside when candidates need to move to the center of the political spectrum to win the general election, said Miringoff.
''The longer and the deeper the Republican candidate has to dig into the conservative base to win the nomination, the harder it's going to be to dig out quickly,'' he said.
REUTERS SYU KP0853