MADISON, Wis. -

The Wisconsin Supreme Court has agreed Friday, to hear a lawsuit by tow unions challenging the constitutionality of Gov. Scott Walker's law effectively ending collective bargaining for most public workers, known as Act 10. 

The fourth District Court of Appeals in April asked the Supreme Court to take it, noting ongoing uncertainty about the law's status.

The case was brought by unions representing Madison school teachers and city of Milwaukee workers. A Dane County circuit judge last year overturned the law as it pertained to local government unions, but it was unclear if the ruling applied outside Madison and Milwaukee.

The Supreme Court could have sent the case back to the appeals court to rule first but decided to hear it directly instead.

The controversial act was at the center of protests at the Capitol in 2011. Nearly 100,000 protesters came to Madison that February. 

The protests triggered Legislative walkouts and multiple recall elections, including a gubernatorial recall that set the record for campaign spending by a single candidate.