When Edward "Ward" Sproat moved into his new office at the U.S. Department of Energy in early 2006, the future of Yucca Mountain looked about as bleak as nuclear winter. The atomic waste storage project, which had never amounted to more than a five-mile-long tunnel through a mountain 90 miles northwest of Las Vegas, had already been hammered by lawsuits and starved of funding. Now it was tainted by scandal and absurdity. A series of incriminating e-mails had revealed how some project scientists may have fudged data to meet deadlines; a federal judge had declared the Environmental Protection Agency's 10,000-year safety timeframe inadequate. If Yucca Mountain is to open, the ruling implied, the EPA must protect the area's creatures for as long as nuclear waste remains deadly — perhaps for as long as 1 million years. Even if, as sometimes happens in 1 million years, those creatures will have mutated to survive it.

A tall, genial diplomat with a full head of white hair, Sproat has spent two decades negotiating on behalf of the nuclear energy industry. He frequently goes before audiences, not all of them friendly, to explain the Energy Department's nuclear-waste strategy, which he does with an equanimity seldom seen in bureaucrats. While serving as vice president of PECO Energy before it merged into Illinois nuclear giant Exelon Energy, he brokered a deal to get the government to pay the utility for storing spent fuel at its reactor sites. And he knows from experience that without a solution to the waste problem, the much-touted nuclear power renaissance, with all its guaranteed plant construction loans and tax breaks promised in the 2005 energy bill, is doomed.

Sproat came into his job with a straightforward but Sisyphean task: To make the government's plan for nuclear waste look respectable again. The surest way to do that was to file a long-overdue license application with the Nuclear Regulatory Commission. And on June 3, 2008 — five years past deadline, but 27 days before Sproat himself had pledged — the Energy Department filed a document more than 8,600 pages long with the commission's licensing board, requesting permission to begin construction of a nuclear waste repository at Yucca Mountain.

Now, the commission has three, possibly four, years to decide whether to grant that license. If it does, whoever holds Sproat's job will submit a second application, asking regulators to approve the actual physical transfer of the waste — a half-century of spent fuel rods from civilian atomic power, plus some military waste — to the facility by train and truck. Its earliest opening date is 2020.

To many observers and proponents of the presumed rebirth of the nuclear power industry, Sproat's accomplishment is a magnificent coup. "He's been fantastic," says Per Peterson, a professor of nuclear engineering at the University of California at Berkeley. "He brought in a kind of pragmatism and competence, and he focused in on the most important thing: to get the license application completed and start the technical review.

"Ward Sproat," Peterson concludes, "is the best thing that's happened to Yucca Mountain in its entire history."

Throughout the summer and fall, while the nuclear industry was still kvelling over Sproat's achievement, another story was unfolding in Nevada, one that could nullify all of Sproat's hard work: Illinois Sen. Barack Obama was plotting to win the state in the presidential election. Key to his strategy was affirming beyond a doubt his opposition to the Yucca Mountain repository.