Both Republican Senate candidates say they would support a resumption of underground nuclear weapons tests, presumably in Nevada, to help modernize the nation's weapons stockpile.

Mike Lee signed a "Peace Through Strength" pledge Monday, crafted by a handful of national security organizations. The pledge consists of several defense policy positions, including protecting national sovereignty, not trying enemy combatants in U.S. courts, energy security and the modernization and testing of the U.S. nuclear arsenal.

"We need to always have our eye on the ball for developing new weapons systems and that is going to require new testing," Lee said in an interview with The

Salt Lake

Tribune .

He said he wouldn't support above-ground testing -- which hasn't been conducted in the United States since 1963 -- but believes the U.S. could conduct underground testing. He said he assumes that would be done at the Nevada Test Site.

"I think we need always to be modernizing our equipment, including our nuclear weapons," Lee said in an interview Tuesday. "I think any time you do that, you have to weigh the risks of it against the benefits. I think the big picture moving forward is you have to update technology and that's going to have some testing with it."

Lee's Republican primary opponent, Tim Bridgewater, agrees and would support underground tests "if it was deemed necessary by our military experts."

"I would support that," Bridgewater said. "I would prefer that we don't have to move down that road, but nuclear weapons are a deterrent, and we shouldn't give up our strong position in the world because more nations are becoming nuclear powers and the greater the deterrent the less likely we ever have to use them."

The issue of weapons testing is sensitive in Utah, as untold number of residents -- who became known as Downwinders -- developed various types of cancer that has been linked to fallout from the Cold War-era weapons tests.

Both Lee and Bridgewater's fathers were Downwinders.

Lee's father, former Reagan administration solicitor general Rex Lee, died of non-Hodgkins lymphoma in 1996.

Lee backtracked somewhat Wednesday evening, saying the statement he signed doesn't specifically call for nuclear detonations -- merely testing, which can be done on weapons systems.

But his statements in the interview were specific to blasts and he left open the option of full-scale tests.

Mary Dickson, a Downwinder and author of the book Exposed, said there is no need to move toward renewed testing.

"I just think that's going completely down the wrong road," she said. "Given the history of what nuclear weapons testing did to the people of this country, I just think it's irresponsible to even talk about ever testing weapons on our soil ever again."

Joe Cirincione, an arms control expert and president of the Ploughshares Fund, said there is no scientific study indicating more nuclear tests are needed.

"We've conducted over 1,000 tests in our history, more than every other nation combined," said Cirincione. "We know more about nuclear weapons than any other nation and the scientific consensus is that our nuclear weapons are safe, secure and astonishingly effective and can be kept that way indefinitely without further explosive tests."

Cirincione is in Utah this week advocating for the ratification of The New START Treaty, an agreement that the Obama administration is pressing the Senate to ratify, which would reduce nuclear arsenals to the lowest levels since the 1950s.

The United States conducted more than 900 weapons tests at the Nevada Test Site up until 1992, when President George H.W. Bush imposed a moratorium on testing.

President Bill Clinton extended the moratorium and in 1995 signed the Comprehensive Test Ban Treaty, prohibiting further testing. The Senate rejected the treaty, but no tests have been conducted.

It is in the U.S. interest, Cirincione said, to be part of a global agreement not to test weapons, because it keeps other countries from improving their weapons and maintains the U.S. strategic advantage.

"As soon as we start testing nuclear weapons, there will be a nuclear test chain that will ripple around the globe, from India to China to North Korea," he said. "If we test, bang! It's off to the races."

But Frank Gaffney, president of the Center for Security Policy, who helped write the "Peace Through Strength" pledge, has argued in favor of modernizing and testing American weapons.

Gaffney, who was a Defense Department official in charge of nuclear weapons programs, argued in an essay that the United States needs to maintain an effective deterrent, but the weapons stockpile is aging and hasn't been tested since 1992.

The Obama administration has requested $80 billion for a 10-year modernization program.

"The trouble is that President Obama says that expenditure will not buy a single new weapon," Gaffney wrote. "Nor will any of it go towards testing the ones we have by exploding any of them underground -- the only way to be absolutely certain they work."