I'm not suggesting that this move will fix Wisconsin's fiscal issues. I agree that the governor might just be supporting this for a petty reason as well. If Wisconsin law protects public unions and the legislature wants to pass a law that differentiates in treatment between public ones and private ones, that's not unconstitutional. Your source of employment is not a protected class. Federal discrimination laws only apply to gender, race, religion, and sexual orientation. I side with the idea of restricting public unions on principle, because the public market is different from a private one. When consumers don't have a choice as to whether they can pay for something or not, the rules have to be different from ones governing the open market.