Act 10, a Wisconsin law enacted in 2011 that limits collective bargaining practices for most public workers, is still making its way through the state court system. A Dane County Judge declared most elements of the the law unconstitutional in Sept. 2012 and a stay was put on enforcing the law. However, the case is now in the hands of the Wisconsin Supreme Court and it appears the stay may be lifted.
Attorneys acting on behalf of the unions feel the law violates the state constitution, while attorneys representing the state say limiting the union's collective bargaining power doesn't stop workers from joining a union. Another issue is whether or not Act 10 is in violation of the home rule clause of the state constitution by requiring workers in the City of Milwaukee to pay higher pension contributions.
There are many constitutional issues involved in labor law disputes, including the right to freedom of association, freedom of speech and equal protection under the law. In general, individuals are allowed to pursue common projects through organizations like trade unions, churches and political parties. At issue in this case is the state's right to limit the union's ability to bargain on behalf of its members.
Source: Journal Sentinel, "Wisconsin Supreme Court considers stay in Act 10 case ", Patrick Marley , November 11, 2013