"He has betrayed his constituents," said Van Dam, a former Utah attorney general, during a news conference in St. George. "How can Utahns trust Sen. Bennett to represent them and vote against testing when he has changed his mind and his vote on this issue four times in the past three months?"

Van Dam accused Bennett of not listening to voters, who say they were subject to the debilitating radiation from nuclear weapons explosions at the Nevada Test Site in the 1950s and '60s.

He said southwest Utah's Washington County endured more fallout from the tests than any of the nation's 4,000-plus counties, all of which received some fallout.

Van Dam said a Bush administration proposal to give Congress the power to authorize preparation of the Nevada site for future testing goes against Utahns' wishes.

The Democratic Senate candidate said he believes the Bush administration plans to move forward with development and testing of new nuclear weapons, including a bunker-buster bomb for incinerating subterranean targets. Such testing, he warns, will rekindle a Cold War-like arms race and make the United States more vulnerable - not less - to attack.

Bennett was unavailable for comment Monday, but Larry Shepherd, his deputy state director in Salt Lake City, said the senator's position on nuclear testing has been consistent.

"In a political year it is amusing that the senator's opponents would attempt to incorrectly label him as pro-testing so they could then turn around and call him a flip-flopper when he introduces legislation that they should agree with," Shepherd said.

Earlier this month, Bennett traveled to St. George to unveil a bill that would make future testing contingent on strict environmental and safety requirements along with input from Utahns.

Bennett also underscored the need for the nation to keep its testing options open at a time when "rogue" nations either possess or are developing their own nuclear weapons.

"I'm not pro-testing," said Bennett during his visit to Utah's Dixie. "I'm anti-nuclear ignorance."

Van Dam said the current testing debate is similar to a 1970s proposal to base MX missiles in a shell-game-like configuration in western Utah. He said Utah's delegation supported the MX proposal until LDS leaders spoke out against it.

"They [the delegation] did the Mormon shuffle and all of them voted against it," Van Dam said.

"I hope the LDS Church examines this latest insanity."

Michelle Thomas, an activist with the fallout victims' group Downwinders, said the debate about nuclear testing should not be partisan.

"Radiation doesn't care who you vote for," Thomas said. "We need to educate people about what happened before and never ever let people be used like a petri dish for a giant scientific experiment. People are not expendable for research."