The second shoe to drop in a national campaign against public employee unions fell yesterday in U.S. District Court in Portland.

Two groups, the Olympia, Wa.-based Freedom Foundation and the Virginia-based National Right to Work Legal Defense Foundation, filed a lawsuit on behalf of a dozen Oregon public employee union members who are seeking the refund of dues collected from them against their wishes.

The defendants in the case are the Oregon Education Association, American Federation of State, Local and Municipal Employees, and Service Employees International Union and their affiliates.

The new lawsuit is an attempt to damage financially groups that are a bulwark of the Democratic Party and is part of a long-running effort to reduce the political might of those unions.

On June 27, the U.S. Supreme Court ruled in Janus vs AFSCME that public employee unions could not collect dues from members who did not want to pay them—even those dues that were merely used to cover the cost of collective bargaining, rather than for explicitly political purposes.

The local lawsuit seeks class action status for all Oregon public employee union members who objected to paying dues and seeks the refund of their dues collected since 2012. The lawsuit does not specify how much money the plaintiffs think they are entitled to but a Freedom Foundation member says the total is "millions." (The lawsuit says that the unions stopped collecting dues from dissident members as of June 27, the date of the Janus ruling.)

"The statute of limitations limits the number of years workers can seek and receive back fees," Freedom Foundation spokesman Aaron Withe said in a statement. "But they're entitled to every penny of what they can recover, and we're aggressively working to make sure they get it."

Representatives of the three Oregon unions did not immediately respond to a request for comment.