Why can the state governments of wisconsin ohio and

Question

Why can the state governments of Wisconsin, Ohio, and Michigan alter the collective bargaining rights of firefighters, police officers, and teachers? 

1. They have voted to keep the Wagner Act out
2. The rulings of the agencies constituted under the Wagner Act aren't legally binding
3. The Wagner Act doesn't apply to state or local government employees
4. The Wagner Act is applicable only to private organizations