The key to winning Nevada's five electoral votes might lie with a ridge of volcanic rock some 90 miles northwest of Las Vegas.

Yucca Mountain (search) rises 4,950 feet over the Nevada desert on federal land where no one lives. Yet a Bush-approved plan to bury high-level nuclear waste there divides voters statewide and threatens President Bush's (search) ability to win the state again.

"This is the issue that will defeat Bush in Nevada," said Sen. Harry Reid, a Nevada Democrat polls show coasting to his fourth term. Bush won here in 2000 by 3.5 percentage points, but polls indicate the race with Sen. John Kerry (search) is neck and neck.

Nevada Attorney General Brian Sandoval, a Republican leading the state's legal challenge to the plan, said he doesn't think it's fair to blame the president for approving the project.

"He made a decision based on the information that was provided to him," Sandoval said.

Yucca Mountain is in line to begin receiving 77,000 tons of the nation's most radioactive waste by 2010. Nevada has battled the plan for decades, but in 2002 Congress and Bush authorized the site.

Kerry has vowed to kill the project if elected, saying he prefers to keep the waste at nuclear power plants across the country.

"It will take a Democratic president to stop this," said Rep. Shelley Berkley, D-Nev.

During his only visit to Nevada in 2000, Bush said any decision on Yucca Mountain would be based on "sound science." Democrats believe the statement was enough to swing voters his way and now contend the president didn't keep his promise.

Sen. John Edwards, a North Carolina Democrat, voted in favor of the repository in 2002. Shortly before he joined the Democratic ticket as Kerry's running mate, Edwards promised to oppose it if he were vice president.

Kerry has opposed the project multiple times, including the crucial 2002 vote that solidified Yucca Mountain's future.

"When it's counted, I've voted no to waste at Yucca Mountain," Kerry said during an August visit to Las Vegas.

However, Republicans point out that Kerry voted in favor of an appropriations bill in 1987 that included a proposal to narrow the number of potential repository sites from three to one — Yucca Mountain.

Bush has accused his opponent of using the issue as "a political poker chip" now and questioned what Kerry might do later. "My point to you is that if they're going to change, one day they may change again," he said.

"John Kerry is trying to take the moral high ground and he cannot ... because of his record," said Sen. John Ensign, R-Nev. "If Yucca Mountain was not an issue, George Bush would win Nevada by 10 points."