The Senate candidate warned that voters’ voices are being “drowned out” by “third-party special interest groups with unlimited spending capability,” and called on his opponent to help him bar big outside spenders from the race.

Another Democrat parroting Senate Majority Leader Harry Reid’s attacks on secret campaign spending? Actually, the Senate hopeful railing against political money was Republican Dan Sullivan of Alaska, who sought — without success — to convince incumbent Democrat Mark Begich to sign a pledge to stop the outside money flooding in.

Sullivan is one of more than half a dozen Republican congressional candidates who have made assaults on big money in politics an important campaign theme. Until now, the issue was almost exclusively a Democratic talking point.

It’s a curious twist that reflects growing voter focus on political money, which has drawn news coverage as midterm spending approaches a record $4 billion, and fresh GOP interest in populist anti-corruption messages that resonate with the tea party.

Leading the way has been none other than GOP Senate Leader Mitch McConnell, of Kentucky, who asserted that “no one in the history of American politics has ever won or lost a campaign on the subject of campaign finance reform.”

McConnell’s campaign has leveled a long list money- and ethics-related attacks against Democrat Alison Lundergan Grimes. These include her invitation to “Obama billionaire” Warren Buffett to join a campaign fundraising event via conference call; her attendance at a “luxurious fundraiser” with Democratic Senator Elizabeth Warren of Massachusetts at the home of a controversial Kentucky businessman, and her alleged “sweetheart deal” to rent a campaign bus at less than market value.

“By his actions, he is recognizing that money in politics is a powerful issue to win elections,” said David Donnelly, president of Every Voice, an advocacy group with an affiliated super PAC that promotes political money limits.

Democrats have rejected these attacks and hammered on unrestricted secret GOP spending, as they did in 2010, with a special focus this time on the billionaire industrialists Charles and David Koch. In the previous midterm, voters collectively shrugged and handed the House majority to Republicans. In this election, polls suggest voters have trouble even identifying the Koch brothers.

But Republicans are now leveling their own assaults on billionaires, special interests and lobbyists. In addition to Sullivan, Republican House candidates Mark Greenberg, who’s challenging incumbent Elizabeth Esty in Connecticut’s 5th District, and Evan Jenkins, running against Rep. Nick J. Rahall II in West Virginia’s 3rd District, have called on their Democratic opponents to sign a “people’s pledge” to discourage outside spending. Not surprisingly, given the success of Democratic super PACs in these midterms, Esty, Rahall and other Democrats presented with such pledges have largely declined.

Republicans have leveled their attacks in fundraising appeals, ads and during debates. In North Carolina, Republican Thom Tillis charged in