LAS VEGAS — The three leading Democratic candidates for president tussled Tuesday over a proposed nuclear waste dump, energy policy and gun use in a restrained debate that explored issues key to voters who will caucus here Saturday.
After a week spent in testy exchanges on the subject of race, the candidates went out of their way to be deferential, opening the debate with a series of acknowledgments in which all agreed that the others were caring candidates supportive of civil rights.
The contenders -- New York Sen. Hillary Rodham Clinton, Illinois Sen. Barack Obama and former North Carolina Sen. John Edwards -- spent much of their time critiquing the Bush administration's policies.
But they did probe differences.
After moderator Brian Williams, the "NBC Nightly News" anchor, asked for their views on the proposed Yucca Mountain nuclear waste dump, Obama vowed to "end the notion" of using the rural Nevada site to deposit nuclear waste.
"I've been clear from the start that Yucca, I think, was a misconceived project," he said.
But Clinton quickly cited her vote against the proposal in 2001. She noted that one of Obama's key supporters had tried to push the project. And she pointed out that Edwards had twice voted in favor of the nuclear site.
"I have consistently and persistently been against Yucca Mountain, and I will make sure it does not come into effect when I'm president," she said.
Edwards, for his part, criticized past statements by Obama that he would be open to the construction of nuclear plants, and by Clinton that she was "agnostic" on the subject.
"I am not for it or agnostic," Edwards said. "I am against building more nuclear power plants, because I do not think we have a safe way to dispose of the waste."
The candidates also skirmished over the 2005 energy bill. Signed by President Bush, it was the first national energy legislation in more than a decade. Obama said he supported it as a way to spur the development of alternative energy sources.
"If we are going to deal with our dependence on foreign oil, then we're going to have to ramp up how we're producing energy here in the United States," the Illinois senator said.
Clinton called the bill a giveaway to the energy industry that had been concocted by Vice President Dick Cheney.
"It was the wrong policy for America," she said. "It was so heavily tilted toward the special interests that many of us, at the time, said, 'You know, that's not going to move us on the path we need.' "
