WASHINGTON (AP) - The Supreme Court Wednesday unanimously upheld the right of a Maine public employees' union to force government workers who are not union members to pay a share of legal fees.

The ruling involves a small fraction of the fee that local affiliates pay to national unions for litigation that may not directly benefit the locals. The fees were challenged by some non-union members who were represented by the National Right to Work Legal Defense Foundation Inc.

The Maine State Employees Association, affiliated with the Service Employees International Union, represents workers in contract negotiations with the state. The court has previously held that people who choose not to join the union still must pay fees to the union because they too are covered by collective bargaining.

But there are some activities, including politics and lobbying, for which unions may not charge nonmembers. The question for the court was whether national litigation costs are among the forbidden charges.

A U.S. district judge and the Boston-based 1st U.S. Circuit Court of Appeals had previously sided with the state. The high court affirmed those rulings Wednesday in an opinion by Hon. Stephen Breyer.

"We've won every step of the way," MSEA Executive Director Tim Belcher said, adding that the decision shows that "we acted legally, in a way that was respectful of (non-union members') rights." He said the decision affirms the law as it has been for a long time.

The petitioners in the case asked the Supreme Court to clarify what union activities employees can be lawfully forced to fund, the Right to Work group said.

Mark Mix, president of the National Right to Work Foundation, said, "America's workers were not well-served by this ruling." But in a statement on the group's Web site, Mix also said, "Because of the narrowness of the issue involved, we are optimistic that collateral damage to employee rights will be minimized."

The case is Locke v. Karass, 07-610.