Yuichiro Kakutani reports for the Washington Free Beacon on Supreme Court victor Mark Janus‘ latest courtroom battle.

The Illinois man who won a landmark Supreme Court case that struck a blow against government unions is back in court fighting to recover the money seized from his paychecks, one of many lawsuits that could cost labor groups more than $100 million.

Mark Janus is asking a federal appeals court to force his former union to return the money that it unconstitutionally deducted from his paychecks. The former child support specialist was the named plaintiff in 2018’s Janus v. American Federation of State, County, and Municipal Employees, Council 31 Supreme Court decision, which declared that public-sector unions may not forcefully collect union contributions without employee consent. Associate Justice Samuel Alito affirmed in the Court’s majority opinion that forcing employees to pay partial dues known as “agency fees” to their unions violates the First Amendment.

Janus is still locked in a legal battle, seeking to recover the thousands of dollars that the union forcefully collected from his paychecks before the 2018 decision. A panel of judges on the Seventh Circuit Court of Appeals recently ruled that unions don’t have to refund dues collected in compliance with the pre-Janus legal statutes. Janus has appealed that judgment, asking for an en banc review to be carried out from every judge on the circuit.