Seventy-seven percent of Nevada voters object to storing nuclear waste in their state, which has no nuclear reactors of its own. Nevada Democrats generally believe that Al Gore lost the state, and hence the election, in 2000, because he failed to stake out a position on the issue. Four years later, John Kerry also lost, because while he had mostly opposed Yucca Mountain, he had intermittently voted to fund it — a history that played neatly into the Bush campaign's portrait of him as a flip-flopper.

During the primaries, it seemed as though Obama might share Kerry's credibility problem. Obama comes from a densely nuclear-powered state, and Exelon's employees contributed nearly $200,000 to his presidential campaign. Obama confirmed his opposition in letters to local newspapers and to Nevada Sen. Harry Reid, but Hillary Clinton still stirred up so much doubt that at a January rally he felt compelled to blurt, "What part of ‘I'm not for Yucca' do you not understand?"

But by the start of the general election campaign, Nevada believed him. "There was none of this slithering around that we'd had with other politicians, saying ‘Well, I just go along with what sound science says,' " says Judy Treichel, the executive director of the Nevada Nuclear Waste Task Force. "He actually had it on his position statement that Yucca Mountain was not an option." By contrast, Arizona Sen. John McCain had always championed the repository, and yet told a reporter in a televised interview that he didn't want nuclear waste rumbling through Phoenix on its way to Nevada. The Obama campaign saturated the airwaves with McCain's NIMBY blip, and Obama won the state by more than 100,000 votes.

It's hard to know exactly how much Yucca Mountain had to do with his victory. "Obviously, there's never one issue that determines how people are going to vote," says Nevada Rep. Shelley Berkley, a fierce Yucca Mountain opponent. "But I believe there was a strong sense that President-elect Barack Obama presented a clear alternative to John McCain's manic obsession with putting waste in Yucca Mountain."

Sen. Reid has now pronounced Yucca Mountain dead, and Berkley believes he's right. Nick Shapiro, a spokesman for Obama's transition team, confirmed by e-mail that Obama believes "Yucca Mountain should not and will not move forward." But it's unclear exactly how Obama will kill the project, which was written into law back in 1987. Treichel thinks the new administration will cut off the repository's funds; Berkley hopes Obama will pull its license application.

"I have not spoken with Obama regarding the license application," Berkley says. "But I would recommend that the administration take a long, hard look at it and see what can be done."

The disposal of high-level nuclear waste — mostly leftovers from atomic fission, as opposed to "crapped out" clothes and contaminated tools — has dogged the industry since the dawn of the atomic age. Waste from the very first reactor experiment, in 1942, still taints the groundwater near its burial site in a forest outside of Chicago; spent fuel rods — zirconium-alloy tubes stuffed with uranium pellets — wait in watery cooling pools and dry concrete casks at 121 operating and decommissioned reactors in 39 states. There was a time when the U.S. government expected the industry to figure out how to extract more fuel from burned-up pellets, as the French and British do today. But not only has reprocessing proved to be disastrously polluting, it separates out fissionable plutonium — and plutonium can be used to make bombs. Proliferation concerns made nuclear waste disposal the government's problem.