Three state of Illinois employees who say they are forced to pay dues to unions of which they’re not members want to join an ongoing lawsuit that seeks to have the Illinois practice ruled unconstitutional.

Mark Janus, Marie Quigley and Brian Trygg claim in a new filing they “are suffering the irreparable harm and injury inherent in a violation of First Amendment rights for which there is no adequate remedy at law.”

The filing argues the Illinois law that declares compulsory fees constitutional should be overturned. The trio wants to join a lawsuit filed last month by Gov. Bruce Rauner.

Rauner filed the lawsuit simultaneously with signing an executive order to stop collecting union “fair share” fees from state employees who are not union members. Unions say the idea behind the fees is to cover the cost of collective bargaining from which all workers benefit regardless of their union membership. Those fees by law are not allowed to be used for political purposes. Rauner has argued that it is impossible to separate the two.

Illinois Attorney General Lisa Madigan has sought to dismiss the case, arguing Rauner’s executive order violates the Illinois constitution and Rauner did not have proper standing. The three employees each pay compulsory fees to three unions targeted in the lawsuit — AFL-CIO, American Federation of State, County and Municipal Employees Council 31 and Teamsters Local 916.

On Monday, Illinois labor painted the new legal push-back as part of a broader anti-union agenda.

“It’s no surprise that corporate-funded, anti-worker organizations are supporting Gov. Rauner’s illegal executive order. The Right To Work Foundation and Illinois Policy Institute are corporate shell groups looking to further erode middle class economic security to boost the objectives of their benefactors,” charged Illinois AFL-CIO President Michael Carrigan in a statement. “We will protect the integrity of the law, our collective bargaining agreements and the rights of all workers from these politically motivated attacks.”

Liberty Justice Center is representing the employees in the case; that not-for-profit group is an arm of the Illinois Policy Institute — which received more than $600,00 from Rauner over five years. After he was elected governor, Rauner hired three Illinois Policy Institute employees.

“Whatever money he gave to the institute was spent long ago,” Jacob Huebert, senior attorney at the Liberty Justice Center, said at a news conference on Monday. ”So the governor does not fund the Liberty Justice Center or the Institute.”

Huebert said he was there to advocate First Amendment protections for his clients.

Anyone who doesn’t want a union to speak for them should not be forced to pay for union speech,” he said. 

Carrigan argued that the issues raised both by Rauner and the intervenors were already decided by the U.S. Supreme Court in Abood v. Detroit Board of Education, a 1977 case. “The concept of charging employees for non-political union representation is permitted under the First Amendment,” Carrigan said. “We are opposed to workers having a free ride where the union is required to represent them without reimbursement for representation expenses that are non-political in nature.”