The Supreme Court reinstated a law in the state of Washington yesterday that gives the state partial legal jurisdiction over the 1.3-million-acre Yakima Indian Reservation.

In a 7-to-2 decision, the court overturned a ruling by the 9th U.S. Circuit Court of Appeals which said the law violated equal protection guarantees of the Constitution because it was based on a so-called uneven "checkerboard" pattern that had no rational basis.

The majority opinion, written by Justice Potter Stewart said, "The lines the state has drawn may well be difficult to administer. But they are no more or less so than many of the classifications that pervade the law of Indian jurisdiction."

Stewart said the law "is fairly calculated to further the state's interest in providing protection to non-Indian citizens living within the boundaries of a reservation while at the same time allwing scope for tribal self-government."

Justice Thurgood Marshall, who was joined in dissent by Justice William J. Brennan Jr., said that "Washington's complex jurisdictional system, dependent on the status of the offender, the location of the crime and the type of offense involved, by no means simplifies law enforcement on the Yakima Reservation. To the contrary, it exacerbates the confusion that the statute was designed to redress."

The dispute arose from a 1971 suit against the state by the Yakima tribe, which contended the state was unnecessarily interfering.

The Yakima Reservation has about 25,000 residents, of which only about 3,000 are Indians. Fourfifths of the 1.3 million acres is held in trust for the Indians by the federal government, with the remainder -- called "fee lands" -- owned privately by Indians and non-Indians.

The Supreme Court ruled March 6, 1978, in a case involving the Suquamish Indian Tribe of Washington that Indian tribes do not have authority to prosectue non-Indians for crimes committed on the reservations.