OLYMPIA, Wash. (AP) _ A teachers strike that has idled 11,000 students for nearly seven weeks, the longest in state history, is raising a muddy legal question for the courts: Can Washington teachers legally strike?

Judges have issued dozens of back-to-work injunctions to end strikes, but nobody really knows the answer to the question. In the past, strikes have usually ended before anybody fought them into the courts.

``That's why you get this confusion about whether it's illegal,'' said Assistant Attorney General David Stolier. ``There's never been a teachers strike that's gotten into the appellate system.''

This case could be different.

The Marysville teachers strike began Sept. 2 and dragged on for weeks with little agreement, particularly on the district's proposal to scrap its local salary structure in favor of the state's scale. Pay for the roughly 700 teachers became the key issue. A group of angry parents joined the district in a bid to make the teachers report to work.

In a court hearing Wednesday, Snohomish County Superior Court Judge Linda Krese scolded both sides and told them to meet for mediation sessions eight hours a day through Sunday _ the 48th day of the strike.

If there was still no agreement, Krese said she would see them in court Monday.

The question of the legality of striking in Washington dates back to 1958, when the state Supreme Court ruled in a case involving a dockworkers strike that public employees in general weren't allowed to walk off the job.

But that high court decision also invited the Legislature to clarify the issue.

Lawmakers set clear rules for some classes of public employees _ police and firefighters can't strike, for example _ but not for teachers.

Mitch Cogdill, an attorney representing the Marysville Education Association, points out that lawmakers gave police and firefighters protections to go with their strike bans.

Their labor disputes can go to binding arbitration so an impartial third party settles the matter. That offsets the advantage employers have in negotiating with workers who can't strike. Teachers, however, can't go to arbitration.

``In that legislative scheme, there was no prohibition against striking,'' Cogdill said. ``We contend the Legislature knew exactly what it was doing.''

He also noted that lawmakers repeatedly declined to pass bills specifically outlawing teacher strikes.

Michael Hoge, an attorney for the Marysville School District, argued the opposite, saying that no right to strike had been upheld.

``Based on extensive research, no cases appear where a court in Washington or elsewhere has found that teachers have a right to strike in the absence of a statutory grant of such right,'' Hoge wrote in a brief to the court. ``The common law against public employee strikes in Washington has never been changed.''

Twenty-four states prohibit teacher strikes, according to the Web site of the Denver-based Education Commission of the States.

One of the nation's longest-running school strikes occurred in Illinois, when teachers in the small community of Homer went on strike for eight months, beginning in October 1986. In that case, substitutes were brought in within two weeks, and the students returned to class.

One reason courts haven't decided the issue more definitively in Washington is that even injunctions that have been issued are rarely enforced.

Typically, defying such an order could draw a contempt citation and a civil fine, which can be appealed. But that's a time-consuming process.

``The whole issue of fines and contempt is not a workable system for these disputes to be solved,'' Cogdill said.

Also, once started, fining teachers for every day missed might add an extra layer of bitterness, further hindering negotiations.

``It still comes back to the first principle,'' Stolier said. ``They have to agree to something. There's no outside force that can make them agree.''