U.S. District Judge William Conley upheld the limits on collective bargaining that allow general employee unions to bargain only on wages, the Milwaukee Journal Sentinel reported. But he found the law violates due process by requiring the unions to hold recertification votes annually and denying them voluntary dues collection.
"So long as the State of Wisconsin continues to afford ordinary certification and dues deductions to mandatory public safety unions with sweeping bargaining rights, there is no rational basis to deny those rights to voluntary general unions with severely restricted bargaining rights," Conley wrote in his opinion.
The law -- pushed by Republican Gov. Scott Walker and passed by Republicans in the state legislature -- caused an uproar last year. Democratic senators fled the state in an unsuccessful effort to deny Walker a quorum, and opponents of the law staged massive protests at the statehouse in Madison.
The protests led to a recall campaign that resulted in Republicans losing their state senate majority. Walker and Lt. Gov. Rebecca Kleefisch, as well as four more GOP state senators, are subject to recall elections this spring.
Notable deaths of 2014 [PHOTOS]