The state Republican Party this week challenged the eligibility of 6,000 registered Montana voters in seven counties that have historically been Democratic strongholds. The move means that those who are registered to vote in Missoula, Butte-Silver Bow, Lewis and Clark, Deerlodge, Glacier or Hill counties and who filled out a change-of-address card with the U.S. Postal Service in the past 18 months will likely have to verify their correct address before the Nov. 4 election. "The integrity of the voting process is something that has to be above reproach to have faith in the system," said Jacob Eaton, executive director of the state GOP. "We aren't trying to prevent anyone from voting. We want people to register properly." Eaton said the move was prompted by Gov. Brian Schweitzer's speech this summer to a group of trial lawyers in Philadelphia. Schweitzer has said he was joking when he told the group that he was able to "turn some dials" to help elect U.S. Sen. Jon Tester. "With Schweitzer's recent comments about rigging the '06 election, that brought everyone in the state to a new level of suspicion and awareness of the integrity of our elections," Eaton said. But Democrats are crying foul, describing the challenge as a "desperate" attempt to keep Montanans from casting ballots in November. "The more people that vote, the better Democrats do," said Kevin O'Brien, a spokesman for the state Democratic Party. "Voting is a right. To prevent people from doing that is desperate. It's their only strategy." Most of the voters being challenged 3,422 are registered in Missoula County, while another 714 are registered in Butte-Silver Bow County. To identify those who aren't living where they are registered to vote, the state Republican Party cross-referenced the statewide voter database with the National Change of Address database, a commercial software system for direct marketers. Affected voters with out-of-county and out-of-state addresses will receive an affidavit asking them to verify their current address, along with a voter registration card to be returned to the elections office by Nov. 4. Failing to do so may require a person to vote provisionally, meaning there's a problem with the ballot.