Maryann Sumi announced on Monday she'll step down on May 30 after nearly 16 years on the bench. Then-Gov. Tommy Thompson appointed her as judge in 1998.
In 2011 she found that Republican lawmakers violated the state open meetings law during the run-up to passing Walker's union measure, which stripped most public workers of nearly all their collective bargaining rights. She stopped the restrictions from being implemented, enraging the GOP.
The conservative-leaning state Supreme Court overturned her ruling two months later. Debate on the case between the justices was so heated that Justice Ann Walsh Bradley accused Justice David Prosser of wrapping his hands around her neck. Prosser said he raised his hands in self-defense and touched her when Bradley moved toward him.