A complaint with the Federal Election Commission filed by the campaign of outgoing U.S. Rep. Joe Schwarz (R-Mich.) targets the campaign of his primary opponent, Tim Walberg.
It also targets one of Walberg's largest supporters: the Club for Growth Political Action Committee or "PAC."
The filing claims the Walberg campaign and the Club for Growth PAC knowingly let donors double-dip: Contributors would give the $2,100 maximum donation to a candidate -- and donate additional money to the PAC with an understanding that the money would go right back to the candidate's coffers.
"That they were supporting a PAC that they know was in existence, for this period at least, primarily to support the same candidates they were giving money to individually," Michigan Campaign Finance Network Executive Director Rich Robinson said, explaining the allegations.
Robinson says even if the accusations prove to be true, they might not violate federal law.
"I don't think it's clear and I think this is an important question," he said.
A spokesman for Walberg's campaign calls the accusations "bogus."
This is the third FEC filing the Schwarz campaign has made against Walberg since the former state legislator unseated Schwarz in the August Republican primary.
Walberg spokesman Joe Wicks says contributions to the campaign fall within federal limits.
But the Schwarz campaign's latest FEC filing claims that's just not the case. In a second accusation, Schwarz's campaign names seven donors it says gave more money to the Club for Growth PAC than is allowed under federal law.
Robinson says it's a "straightforward matter" to determine the veracity of those charges.
Our own examination of federal campaign records shows four of those seven donors named did give more than the $5,000 limit.
That determination -- and a determination on the 'double-dipping' allegations -- are ultimately up to the Federal Election Commission.
"The ruling that comes out of this will be an important precedent going forward," Robinson said.
But an FEC spokeswoman says there's really no way to tell just when that ruling will come down.