Mark Miller has decided to step down from his post as Senate Democratic leader.
Miller's office issued a statement Wednesday saying he plans to quit his post when the current legislative session ends in December.
The Monona Democrat ran unopposed in Tuesday's elections. The statement doesn't say why he chose to quit his leadership position and his spokeswoman didn't immediately return telephone messages.
Miller served as Senate Democrats' leader when they fled the state in 2011 to protest Republican Gov. Scott Walker's contentious law that stripped most public workers of nearly all their union rights.
He helped Democrats seize the Senate majority last June in recall elections stemming from the union law fight.
Republicans took the chamber back in Tuesday's elections, though.