EVEN BEFORE the Supreme Court decided the case of Nancy Cruzan last month, a legislator in Washington State had introduced a bill to expand that state's right-to-die law -- and more. The bill died in committee, but now citizens in Seattle have taken matters into their own hands and begun a complicated initiative procedure to get the proposal on the ballot. If they succeed, the state may have the most far-reaching law of its kind in the country.

Washington now allows an alert patient who is terminally ill -- within six months of dying -- to request the withdrawal of life-support systems. The law also makes provision for such decisions to be made by others if a patient is unable to act. The bill that died in committee earlier this year would have expanded the definition of "life-support systems" to include artificial hydration and feeding and of "terminally ill" to include comatose or a persistent vegetative state. The measure's final provision, and its most controversial, would allow alert and competent patients who are within six months of death to ask for and receive active medical assistance in dying. The last provision for "medically-assisted death" -- euthanasia -- is strongly opposed by medical groups and some churches.

All it takes to force action on this proposal is 150,001 signatures on a petition by the end of the year. Organizers, who started only in May, already have 60,000 and expect to meet the goal easily. If the signatures are verified, the proposal goes to the legislature, and if it is not enacted unamended it will go on the ballot in November of 1991.

The Washington initiative process is fast and decisive. But on a subject as controversial and morally weighted as euthanasia -- not a single state now authorizes it -- there should be more careful consideration than an up or down vote on the bill as drafted. There is virtue in a lot of debate, committee hearings with witnesses, suggestions for alternatives or amendments and a final bill that represents a broad consensus. That may yet happen in Washington, for the legislature can pass its own bill and put it on the ballot as an alternative to the initiative language.

In any event, citizens have forced a debate, and it will be resolved in 16 months. Organizers of the initiative believe that the voters are ahead of their elected representatives on this issue. The process in Washington will provide a telling test.