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Former New York Mayor Rudy Giuliani won the strongest applause at Tuesday night's first-in-the-South Republican primary debate when he lashed out at Texas Rep. Ron Paul for suggesting that the United States' non-interventionist policy invited the Sept. 11, 2001, terrorist attacks.

"They attack us because we've been over there. We've been bombing Iraq for 10 years. ... We've been in the Middle East," Paul said in explaining his opposition to going to war in Iraq. "Right now, we're building an embassy in Iraq that is bigger than the Vatican. We're building 14 permanent bases. What would we say here if China was doing this in our country or in the Gulf of Mexico? We would be objecting.

"They are delighted that we're over there because Usama bin Laden has said, 'I'm glad you're over on our sand because we can target you so much easier.' They have already now since that time they've killed 3,400 of our men and I don't think it was necessary," he continued.

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"That's really an extraordinary statement," Giuliani said, interrupting FOX News panelist Wendell Goler. "That's really an extraordinary statement, as someone who lived through the attack of Sept. 11, that we invited the attack because we were attacking Iraq. I don't think I have ever heard that before and I have heard some pretty absurd explanations for Sept. 11. I would ask the congressman withdraw that comment and tell us that he didn't really mean that."

Paul did not, eliciting a flurry of candidates seeking to get their 30 seconds to rebut him.

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Finally, Colorado Rep. Tom Tancredo managed to get in his two cents when he responded to a question saying that reducing U.S. dependence on petroleum would not only help with global warming, but is a national security issue.

"My dear friend Ron here, I dearly love and really respect, but I'll tell you: I just have to disagree with you, Ron, about the issue of whether ... Israel existed or didn't, whether or not we were in Iraq or not, they would be trying to kill us, because it is a dictate of their religion, at least a part of it. And we have to defend ourselves," he said.

PHOTO ESSAY: Candidates Face Off in First-in-the-South GOP Primary Debate of 2008 Election

Low Blows and High Fives

The debate, held at the University of South Carolina's Koger Center for the Arts in Columbia, S.C., had some feisty moments as the Republican primary candidates sought to distinguish themselves in a crowded field. Tancredo took another shot at fellow GOP candidates when he said he is surprised at the number of conversions toward his tough position on illegal immigration as well as abortion and gun control.

Learn more about the candidates in FOXNews.com's Keep an Eye on the Issues Center.

"I trust those conversions when they happen on the road to Damascus and not on the road to Des Moines," he said.

Former Arkansas Gov. Mike Huckabee also was able to slip in a criticism of the congressional members at the debate, saying Congress has "spent money like John Edwards at a beauty shop," a slam on the Democratic presidential candidate who earned unwanted scrutiny for spending $400 of campaign money on a haircut.

It was a one-up to Arizona Sen. John McCain who had quipped earlier that he has spoken with sailors who take offense at being accused of ever being so drunk as to spend as much as Congress.

"We didn't lose the 2006 election because of the war in Iraq. We lost it because we in the Republican Party came to Washington to change government, and government changed us," McCain said. "We let spending go out of control. We spent money like a drunken sailor. Although I never knew a sailor — drunk or sober — with the imagination of my colleagues."

Former Virginia Gov. Jim Gilmore tried to attract some attention by calling out so-called conservatives for taking non-conservative positions. Prodded to name names, Gilmore referred to "Rudy McRomney," combining the names of McCain, Giuliani and former Massachusetts Gov. Mitt Romney. Gilmore cited Giuliani's position on abortion rights, Huckabee's decision to raise taxes in Arkansas and Romney's mandate requiring universal health care while he served as the governor of Massachusetts.

"Did I get left out?" McCain asked to laughter.

"I'll come back," Gilmore retorted.

Giuliani, however, took the accusation in stride.

"First of all, I think 'Rudy McRomney' wouldn't make a bad ticket, and I like the order," he said before scolding Gimore. "Republicans should be uniting to make certain that what the liberal media is talking about — our inevitable defeat — doesn't happen."

"It's a form of flattery to be attacked but I wish my name would get in the moniker. ... I could use the bump," Huckabee said, adding that he doesn't apologize for getting 94 tax decreases while being a Republican governor in a Democratic state, even though he raised gasoline taxes in his state.

"We raised gasoline taxes in my state to build a road program that we desperately needed. But 80 percent of the people of my state voted for it," he said. "Do I apologize for going along with what 80 percent of the people of my state supported? No."

Serious Issues, Serious Answers

In the 90-minute debate, answers were limited to one minute and the candidates spoke quickly to try to make their points, win their argument and avoid the dreaded bell that rung when their time was up.

All the candidates at Tuesday night's debate shared one common agenda: They wanted to get out of the question-and-answer session unscathed and hopefully in a better position than when they started.

Much of the attacks were on McCain. The Arizona senator was hit for his positions on immigration, campaign finance and government spending, among other items.

"My fear is that McCain-Kennedy would do to immigration what McCain-Feingold has done to campaign finance and money in politics — and that's bad," Romney said.

McCain got his opportunity to counterattack later with a cutting barb at Romney. "I have not changed my position on even-numbered years or changed because of the different offices that I may be running for."

While the candidates were able to get in their tackles, they did speak seriously on several topics. California Rep. Duncan Hunter, who wrote the border fence bill signed by President Bush in October, criticized the Bush administration for not moving more quickly to build the barrier.

"We need to be able to ask people when they want to come into America: Knock on the front door because the back door's going to be closed," Hunter said.

McCain sought to solidify his position as the frontrunner in the South Carolina polls by saying he is willing to be the last man standing in favor of war.

"If we fail in Iraq we will see Iraq become a center for Al Qaeda, chaos, genocide in the region and they will follow us home," McCain said. "Americans are frustrated because of the mishandling of these war, but America's vital national security interests are at stake.

Taking a tough stance on Iraq, former Wisconsin Gov. and former Health and Human Services Secretary Tommy Thompson said he wants to hold the government accountable by letting the Iraq parliament vote on whether U.S. troops should remain.

"The United States government has been there for four years. We've lost many individuals — 3,400 individuals as of today — and it's time for the al-Maliki (government) to vote whether or not they want us in the fifth year to stay in their country, or whether or not they want us to go home," he said.

But Kansas Sen. Sen. Sam Brownback said the way the war is being conducted is not sustainable. In an appeal to bipartisanship, Brownback said that the parties in the United States need to pull together at home to win in Iraq.

"We will win if we can pull together — and we can win the war," he said. "It's difficult for a democracy, particularly in the United States, for us to win with one party for the war and one party against the war."

Nightmarish Vision

The candidates also were asked to respond to a hypothetical scenario — homicide bombings at three shopping centers near major U.S. cities. With hundreds dead and thousands injured, a fourth attack is averted when the attackers are captured off the Florida coast and taken to Guantanamo Bay to be questioned. U.S. intelligence believes another, larger attack is planned and could come at any time. How aggressively should the detainees be interrogated about the where the next attack might be?

First to answer was McCain, a former POW in Vietnam who opposes the use of torture.

"We could never gain as much we would gain from that torture as we lose in world opinion. We do not torture people," he said. "It's not about the terrorists, it's about us. It's about what kind of country we are. And a fact: The more physical pain you inflict on someone, the more they're going to tell you what they think you want to know."

"In the hypothetical that you gave me, which assumes that we know that there's going to be another attack and these people know about it, I would tell the people who had to do the interrogation to use every method they could think of. Shouldn't be torture, but every method they can think of," Giuliani said, adding that that could include waterboarding. "I've seen what can happen when you make a mistake about this, and I don't want to see another 3,000 people dead in New York or anyplace else."

"You said the person is going to be in Guantanamo. I'm glad they're at Guantanamo. I don't want them on our soil. I want them in Guantanamo where they don't get the access to lawyers they get when they're on our soil. I don't want them in our prisons. I want them there. Some people have said we ought to close Guantanamo. My view is, we ought to double Guantanamo," Romney said.

"Let me just say, this would take a one-minute conversation with the secretary of defense," Hunter said. "I would call him up or call him in, I would say to SecDef, in terms of getting information that would save American lives even if it involves very high-pressure techniques, one sentence: 'Get the information.'"

"First of all, let me say that I would go to the U.N., but it would be to state an opinion and to take advantage of our rights under international law, not to go ask for permission," Gilmore added.

Life-Saving Debate

Romney and Giuliani both were forced to defend their positions on abortion. Romney said the voters, not the courts, should determine whether abortion is permitted.

"I can tell you that I've looked at this long and hard. I've always been personally pro-life. I've taught that to others, it's been part of my faith. The question for me was: What should government do in this kind of setting? And the Supreme Court stepped in and took a decision, and I said I'd support that decision," Romney said. "And then I watched the impact of that decision as I was governor of Massachusetts. ... Roe v. Wade has gone to such an extent that we've cheapened the value of human life."

"There are people, millions and millions of Americans, who are of as good conscience as we are, who make a different choice about abortion. And I think in a country where you want to keep government out of people's lives, or government out of people's lives from the point of view of coercion, you have to respect that," Giuliani said.

That answer did not satisfy Huckabee.

"[Giuliani] has been honest about his opinion; he's been honest about his position. And I think that's a healthy thing for our party and for this debate. But I'm pro-life because I believe life begins at conception. And I believe that we should do everything possible to protect that life .... and that's why we go out for the 12-year-old Boy Scout in North Carolina when he's lost. That's why we look for the 13 miners in Sago, W.Va., when the mine explodes. That's why we go looking for the hikers on Mount Hood: Because we value life," the former governor said.

Thompson, who added that embryonic stem cell research is a promising science, but adult stem cells appear to have the same characteristics as embryonic stem cells.

"Until this research is done, we do not have to destroy any more embryos. There is enough lines right now, and capable with this other research going on, that embryonic stem cells, along with adult stem cells, cord blood and amniotic fluid can continue," he said.

Learn more about the candidates in FOXNews.com's Keep an Eye on the Issues Center.