WASHINGTON -- Supreme Court justices indicated Wednesday that they are inclined to uphold a Washington state law preventing unions from using fees they get from workers for political activities.

The case involves a few thousand teachers and other education employees who are in the bargaining unit and thus represented by the more than 70,000-member Washington Education Association -- but who have chosen not to join the union.

Workers can't be forced to join or pay for the union's political activism, but they can be charged a fee for labor negotiations that affect them.

The narrow issue before the justices is whether, as Washington law prescribed, employees must opt in, or affirmatively consent, to having some of their money used in election campaigns.

The Washington Supreme Court struck down the law, saying the union's offer to reduce fees for any non-member who registers an objection to the political spending was sufficient.

"States have considerable discretion in determining how to protect First Amendment constitutional rights. It seems to me Washington acted quite properly," Justice Anthony Kennedy said, reflecting a view seemingly shared by at least five other justices.

The provision was a small part of a comprehensive campaign finance reform law that state voters approved in 1992.

Washington Attorney General Robert McKenna said there's no reason to think workers who decide not to join the union would want to support its political activities. "They shouldn't be required to say no twice," McKenna said.

In practice, the union uses the money only for ballot initiatives, not for candidate elections. Campaign contributions to union-backed candidates come from a separate political action committee.

John West, representing the union, said workers rights already are protected because they can object to their money being spent on politics.

The union is the state's largest teachers union, representing teachers and other employees of public schools and colleges. Less than 5 percent of employees the union represents choose not to be members, the union said.

The cases are Davenport v. Washington Education Association, 05-1589, and Washington v. Washington Education Association, 05-1657.