From California to Maine, unions used their political muscle in the recent elections to help install Democratic governors, build labor-friendly majorities in state legislatures and defeat ballot initiatives against them. The combination of union money and member mobilization helped Democrats take control of state legislatures in Maine and Minnesota. In Michigan, voters repealed a law that allowed cities in financial distress to suspend collective bargaining contracts. But unions lost there on an effort to make collective bargaining rights a part of the state constitution. In New Hampshire, unions helped Maggie Hassan win the governor's race. Unions spent millions backing Hassan...