When Maggie Hassan won the New Hampshire governor's race, it wasn't just a victory for her fellow Democrats.
Unions spent millions backing Mrs. Hassan with television ads and an extensive get-out-the-vote operation because she opposes a right-to-work bill to ban labor-management contracts that require affected workers to be union members or pay union fees.
From California to Maine, unions used their political muscle 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 In Michigan, voters repealed a law that allowed cities in financial distress to suspend collective bargaining contracts.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 perhaps their most important victory, unions defeated a California ballot measure that would have prohibited them from collecting money for political purposes through payroll deductions.
"The unions must be fairly happy with themselves," said Gary Chaison, professor of industrial relations at Clark University in Worcester, Mass. "These are positive signs, particularly saving their political life in California."
While re-electing President Obama was labor's highest Election Day priority, unions invested major resources in state races where they have been fighting efforts by governors and state lawmakers to restrict bargaining rights or dilute union power.
The victories could mark a turnaround of sorts for unions nearly two years after Wisconsin Gov. Scott Walker announced plans to strip teachers, nurses and other public employees of most collective bargaining rights. Mr. Walker, a Republican, justified the move as necessary to stem the state's budget shortfall.
Since then, unions have been fighting dozens of measures across the country targeting labor rights. They failed earlier this year to recall Mr. Walker from office, but a judge has declared parts of the Wisconsin law unconstitutional.
It wasn't all good news for unions on Election Night. They lost a first-of-its-kind ballot effort in Michigan that would have enshrined collective bargaining rights in the state constitution.
Unions saw the measure as a way to prevent Republicans from passing a right-to-work law that would have ended unions' ability to collect fees from nonunion workers. Critics said it would cause the repeal of dozens of state laws and interfere with local officials trying to control their budgets. One union-backed group spent at least $6.5 million on TV ads supporting it.
Labor's victories came at a steep cost, too. Unions and other Democratic interests poured at least $75 million in the effort to defeat California's Proposition 32.