Act 10, also known as the Wisconsin Budget Repair Bill, was passed in June of 2011.
Update: Governor Walker reacted to the decision saying "As we've said all along, Act 10 is constitutional. Today's court ruling is a victory for Wisconsin taxpayers. The provisions contained in Act 10, which have been upheld in federal court, were vital in balancing Wisconsin's $3.6 billion budget deficit without increasing taxes, without massive public employee layoffs, and without cuts to programs like Medicaid. With this ruling behind us, we can now focus on the next state budget, which will invest in priorities to move our state forward."
Shortly after the decision, Attorney General J.B. Van Hollen stated: "For nearly two years, those opposing Act 10 have tried every angle to have it struck down and invalidated. Today's decision by the Seventh Circuit confirms what I have stated from the beginning. Act 10 is constitutional. While there are no guarantees, it is my hope that this decision will pave the way for resolving any remaining challenges in a manner that supports the legislative decisions made by our elected officials."
A link to the decision is available here.