US:Republican presidential candidates have sought to distance themselves from President George Bush, although most expressed support for a continued US presence in Iraq and refused to rule out using nuclear weapons to attack Iran, writes Denis Stauntonin Manchester, New Hampshire.
In their third debate on Tuesday, candidates took the stage in Manchester, New Hampshire, to discuss faith, foreign policy, healthcare and immigration.
Front-runners Rudy Giuliani, John McCain and Mitt Romney dominated the evening, with Mr McCain setting himself apart from other candidates by expressing support for a comprehensive immigration reform currently under debate in the Senate.
Mr Giuliani said: "The problem with this immigration plan is it has no real unifying purpose. It's a typical Washington mess. It's everybody compromises . . . and when you look at these compromises, it is quite possible it will make things worse."
Mr Romney also criticised the bill, which would allow most of an estimated 12 million illegal immigrants to remain in the US and eventually apply for citizenship.
"Every illegal alien, almost every one, under this bill, gets to stay here," Mr Romney said. "That's not fair to the millions and millions of people around the world that would love to come here, join with family members, bring skill and education that we need."
Mr McCain, who worked with Democrat senator Edward Kennedy last year on a similar proposal, insisted that to do nothing about immigration would make the US less safe and would grant an effective amnesty to illegal immigrants now in the country.
"What we have done is what you expect us to do, my friends, and that's come together . . . and sit down and figure out an approach to this problem . . . This isn't the bill that I would have written, but it does satisfy our national security challenges, which are severe and intense," he said.
For the most part, however, the candidates were broadly in agreement on the big issues, with only libertarian congressman Ron Paul opposing Mr Bush's surge of troops in Iraq. Mr Paul was also the only candidate who rejected the use of a tactical nuclear weapon to destroy any nuclear weapons capability Iran might develop in the future.
All but Mr McCain agreed that English should be the official language of the US and all 10 said that gays and lesbians should not be allowed to serve openly in the military.
The candidates were also at one in their eagerness to distance themselves from Mr Bush, who remains popular among Republicans but has slumped to a 29 per cent approval rating overall.
Mr McCain and Mr Romney criticised Mr Bush's conduct of the war and former Arkansas governor Mike Huckabee appeared to blame the president for the Republicans' loss of Congress last November.
"We didn't do what we were hired to do and the people fired us," Mr Huckabee said. "We've lost credibility, the way we bungled Katrina, the fact that there was corruption that was unchecked in Washington and the fact that there was a feeling that there was not a proper handling of the Iraqi war in all of its details and the indifference to people pouring over our borders."
Most candidates said that Mr Bush should pardon Lewis "Scooter" Libby, vice-president Dick Cheney's former chief of staff who was sentenced this week to 2½ years in prison for lying under oath and obstructing an investigation into the leaking of a CIA operative's identity.
The White House has said that Mr Bush has no immediate plans to pardon Libby, although the president said he felt "terrible" after the sentence was handed down.
The most dramatic moment in the debate came when lightning struck and crackled the sound system as Mr Giuliani was preparing to answer a question about the Catholic hierarchy's criticism of his support for abortion rights.
"For someone who went to parochial schools all his life, this is a very frightening thing that's happening right now," Mr Giuliani said.