LAS VEGAS — Anticipating tough questioning from her opponents as they attempt to chip away at her lopsided lead in the polls, Sen. Hillary Clinton began Thursday night’s Democratic presidential debate with a joke about her wardrobe.”This pantsuit, it’s asbestos tonight,” Clinton quipped.

She needed it.

Trying to reel in the Democratic frontrunner, who in this week’s Nevada Poll had a more than 2-to-1 lead over her nearest competitor, Clinton’s opponents sought in a two-hour nationally televised debate on CNN to further erode her fading aura of invincibility.

Sen. Barack Obama, D-Ill., was the first to come out swinging in the debate, which comes roughly two months before next January’s Nevada caucus.

“What the American people are looking for right now is straight answers to tough questions, and that is not what we’ve seen out of Sen. Clinton on a host of issues,” Obama said, referring to Clinton’s hedged answers in past debates on Social Security and whether undocumented immigrants should receive driver’s licenses.

Former Sen. John Edwards, D-N.C., warmed to the same theme in his opening remarks.

“Sen. Clinton says she will end the war,” Edwards said. “She also says she will continue to keep combat troops in Iraq and continue combat missions in Iraq. She says she will turn up the heat on George Bush and the Republicans, but when the crucial vote came on stopping Bush, Cheney and the neocons … she voted with Bush and Cheney.”

After deflecting her opponent’s charges, in part by pointing to what she views as shortcomings in their own records, Clinton got her best opportunity to turn back the assault when asked to respond to criticism that her campaign has exploited gender by accusing the “all-boys club” of presidential politics of “piling on” by attacking her.

“I’m not playing, as some people say, the gender card here in Las Vegas,” said Clinton, D-N.Y. “I’m just trying to play the winning card.”

“I understand very well that people are not attacking me because I’m a woman — they’re attacking me because I’m ahead,” Clinton added, drawing loud applause and laughter from the audience of about 2,500 at the University of Nevada Las Vegas’ Cox Pavilion.

“You know, as Harry Truman famously said, ‘If you can’t stand the heat, get out of the kitchen. And I feel very comfortable in the kitchen. ”

While the leading candidates’ thrusts and parries dominated the early portions of the debate, the seven contenders on stage also addressed a broad range of other issues such as the war in Iraq, universal health care, illegal immigration and the growing tensions in Pakistan.

A bemused Sen. Joe Biden, D-Del., encouraged his colleagues to move beyond the verbal sniping to address the substantive issues at stake in 2008.

“The American people don’t give a darn about any of this stuff that’s going on up here,” Biden said.

“They’re sitting down at their tables at night, they put their kids to bed and they’re worried about whether or not their child is going to run into a drug dealer on the way to school. They’re worried about whether or not they’re going to be able to pay for their mortgage because, even if they didn’t have one of those subprime mortgages, things are looking bad for them.

“They’re worried about whether they’re going to keep their job. And they’re worried about whether their son in the National Guard’s going to get killed in Iraq.”

Sen. Christopher Dodd, D-Conn., joined Biden in decrying the debate’s “shrillness.”

“When a campaign is about turning up the heat or who’s angrier or who’s yelling louder, the American people turn off,” Dodd said.

Similarly, Gov. Bill Richardson of New Mexico also faulted the other candidates for “going after each other on character and trust.”

“It seems that John wants to start a class war,” Richardson said. “It seems that Barack wants to start a generational war. It seems that Sen. Clinton, with all due respect on her plan on Iraq, doesn’t end the war. All I want to do is give peace a chance.”

The fundamental choice in the election, Edwards said, is to select a candidate who “will take on this system and change it so that it’s no longer … corrupt and rigged against the interests of the American people.”

Rep. Dennis Kucinich, D-Ohio, who, as in past debates, got short shrift in the questions posed to him and in the attendant air time he received, characterized himself as the race’s “candidate of workers.”

“A Kucinich administration will mean a workers’ White House,” Kucinich said. “Right now wealth is being accelerated upwards, and I’m the one candidate in the race who comes right from the working class and can address those needs directly because I remember where I came from.”

An eighth candidate in the Democratic presidential contest, former U.S. Sen. Mike Gravel of Alaska, was not invited to participate in the debate after falling short of one of the criteria — having raised at least $1 million in campaign contributions. As of Sept. 30, Gravel had raised only one-fourth that amount.