A county judge on Thursday struck down Wisconsin's controversial union law that curbs many collective bargaining rights for state workers.

Dane County Circuit Judge Maryann Sumi, who previously had placed a stay on the law, ruled that Republicans violated Wisconsin's open-meetings law when they passed the law in March, according to the Milwaukee Journal Sentinel


"This decision explains why it is necessary to void the legislative actions flowing from those violations," wrote Sumi.

The judge's ruling is the latest twist in the struggle over the law, which was championed by new GOP Gov. Scott Walker. 

The legal proceedings have yet to be settled: the state Supreme Court will hear arguments on June 6 on whether to take up the case, the Journal Sentinel reported.

Walker initially earned a major victory over Democrats by passing the law but has faced backlash among union leaders who say the law is an "assault" on the labor movement.

The law gained national attention after opponents organized massive protests against it. Both political parties have used the law in a proxy debate over the nation's federal deficit and debt.