The scene was the headquarters of GT Solar Technologies in Merrimack, New Hampshire. It was August 17, and former New York City mayor Rudolph Giuliani--the current frontrunner for the 2008 Republican presidential nomination--was taking questions from a small audience. A woman with short brown hair said she didn't understand how being "on offense" in the war on terrorism "means having 3,500 of our troops being killed in Iraq and Afghanistan." She said she didn't understand "that way of thinking." "We're not accomplishing anything," she said. "And we know that."

A typical pol might have dodged the woman's comment and moved on to his stump speech. Not Giuliani. He not only tackled the question--he also took on the questioner. "I would say just the opposite," Giuliani said. "I would say we know that we're accomplishing things. But I would not tell our troops in Iraq that they're not accomplishing anything. I think that's a terrible thing to do."

The woman tried to interrupt.

"No, no, no," Giuliani went on. "You got to let me finish the answer now. You asked the question, let me finish the answer. You might not like the answer, but you got to let me finish it. I think it's a mistake, both substantively and emotionally, both, to tell our troops that they're accomplishing nothing in Iraq--and a very serious overstatement. Which I think comes from, in a large way, the way in which the media covers it. I think they"--the troops--"have accomplished a great deal in Iraq." American troops deposed Saddam Hussein, "who was a major pillar of support for Islamic terrorism," Giuliani said. The victory in Iraq helped convince Libyan dictator Muammar Qaddafi to give up his weapons of mass destruction and terrorist support--"another major achievement of the men and women who you say are accomplishing very little in Iraq." Third, Giuliani said, fighting Al Qaeda In Iraq and al Qaeda remnants in Afghanistan so far has prevented Islamic terrorists from again striking America.

Giuliani's response helps explain his appeal--and hints at liabilities. Hizzoner took much of last week off, resting in preparation for the grueling campaign season that begins after Labor Day. But the former mayor and his top campaign staff enter the fall confident they will prevail in the race for the GOP nomination. Giuliani appears to have halted his slippage in national polls and reasserted his national lead at about 30 percent support. He expects to raise more money from contributors than any other Republican candidate during the third quarter, which ends on September 30. And his articulate, aggressive stance on terrorism, national security, and illegal immigration is bound to resonate with the majority of Republican primary voters who list those issues as their top concerns.

So Giuliani is the Republican frontrunner--but he's also a highly vulnerable frontrunner. Polls show only a plurality of Republican voters understands that Giuliani is pro-choice in a pro-life party. As that number rises, there's a chance his support will decline. Also, Giuliani's main rivals for the nomination, former Massachusetts governor Mitt Romney and former Tennessee senator Fred Thompson, have only just begun to attack the mayor on immigration (Romney) and gun control (Thompson). Even Arizona senator John McCain, whom the Giuliani campaign considers down but not out in the fight for 2008, got into the fray. In a letter to voters released last week, McCain wrote: "I believe it would be a grave mistake for our party to lose focus by nominating a candidate whose commitment to restoring the proper role of the courts can credibly be questioned." McCain didn't say who that candidate might be, but he wasn't talking about Kansas senator Sam Brownback.