The long and short of it is, Naomi Marquez lost the part. She lost the part because the Screen Actors Guild (SAG) screwed up, and now the Supreme Court has agreed to get into the act. These are the facts:

In the late summer of 1994, the Seattle-based producers of a television series called "Medicine Ball" needed an actress for a bit part. Marquez successfully auditioned for the role. It would pay her $550.In accordance with industry procedures, she called Seattle's SAG office in September, only to learn that she would have to pay $500 in union initiation fees and dues BEFORE the taping. She didn't have the $500. Sorry about that, said SAG. Could she pay when she got her "Medicine Ball" check in October? No way, said SAG. Some now, some later? Gedouddahere, said SAG.

At this point, Marquez got in touch with Hugh Reilly of the National Right to Work Legal Foundation. He wrote a letter reminding SAG that under federal law, Marquez could not be required to join a union as a condition of employment. SAG could demand only that the actress pay an "agency fee" to the union.

The union got the word. SAG's counsel belatedly advised the producers that Marquez was now OK. Alas, the show already had been taped, with another actress in the role. Hell hath no fury like an actress spurned. She sued. She lost in the trial court and lost again in the 9th Circuit last August, but last month the Supreme Court agreed to hear her case.

By nice coincidence, on the same day the high court granted her petition for review the court heard argument in another case involving compulsory unionism and agency fees. Still a third case, Buzenius vs. NLRB, will be kept on hold for the next few months while decisions are sorted out.

The Right to Work Legal Foundation finds itself in high cotton. The several cases may produce a defining "bright line" opinion on the powers of a union and the rights of dissident workers. Marquez may have triggered the biggest explosion of law in this field since the rights of dissidents first gained protection in 1961.

The opposing positions are well-known. On one side is the evil of compulsory unionism. In a free country, no person should be compelled to become and remain "a member in good standing" of a labor union in order to get or to hold a job. Nevertheless, many collective-bargaining agreements, including those negotiated by the Screen Actors Guild, contain that provision.

On the other side is the free-rider - the nonunion employee who benefits from a union-negotiated bargaining agreement but pays nothing toward the union's expenses.

The courts have approved a compromise: Rosie the Riveter cannot be compelled to join a union, but she can be compelled to pay for the services the union provides. If her dues are $100 a month, and if she can show that the union spends only $80 per capita on union duties, she gets $20 back. In theory. If the union endorses Bill Clinton, at least it's not on her nickel.

Things never work out so neatly. Lawsuits have raged up and down the judicial circuits on the defining and calculation of "nongermane" outlays. May the costs of a union picnic be factored into the accounting? What about a union's monthly newsletter? If a union expends substantial sums to organize Plant A in Akron, may these costs be imposed on members of the local at Plant B in Dayton?

Other questions arise. The case that was argued on March 23 involved Robert A. Miller and 152 other nonunion pilots for Delta Air Lines. They objected to paying for certain expenses of the Air Line Pilots Association. In their view, these expenses simply were nongermane to collective bargaining, contract administration or resolution of grievances.

The union said yes, the expenses were germane. Then the union hired a professional arbitrator to make a nonbinding recommendation. The dissidents said, We don't like your kind of arbitration; we want a federal judge to settle this dispute. The union said, First you must go before the arbitrator. No way, said the dissidents. On such stuff the high court often feeds.

From their questions, the justices seemed inclined to feel that the dissident pilots had a good point, but questions from the bench can be deceptive. The circuit courts are sharply divided on the whole business of the fees that nonunion workers must pay for union services. I would agree that dissidents should pay a fee for what they get, but they shouldn't be stuck with the union president's bar bill at a political convention.