After every other case had been tried, the crowded room had emptied and the three shackled prisoners in orange jumpsuits and cuffs had been escorted away, Isaiah Wynne sat before the judge.

On a frigid December afternoon in Spokane Tribal Court — a squat clapboard building on a gravelly road at the center of this rural town, where the warm aroma of wood-burning stoves cut the cold air — Wynne held a red folder bulging with papers. His black hair was folded neatly into two long braids; a crisscross of tribal tattoos peeked out from under his black shirtsleeves. He sat beside his lawyer, Michael Beegle, who wore a suit and cowboy boots.

Wynne faced three charges of possession of marijuana with intent to sell. But his attorney argued that, despite the Spokane Tribe’s explicit Law and Order Code (PDF) stating that marijuana is illegal for use on the reservation, the charges against him should be dismissed because of the tribe’s historical use of the plant for medicinal and spiritual purposes. In fact, a talking circle of elders was called here recently to discuss whether that was true.

“I think there’s substantial evidence that there is historical use,” Beegle said.

It’s a scene likely to be replicated in tribal courts across Washington, one of two states in the country where people can legally use, distribute and possess marijuana. There are 29 federally recognized tribes in the state. And marijuana remains illegal to possess — for medical purposes or otherwise — under federal and tribal law.

Last week the Yakama Nation — which has a 1.2 million–acre reservation in south-central Washington — said it would ban marijuana on all its ceded lands, a massive area that spans more than 10 counties and includes several cities (PDF). Though the tribe ceded most of that land to the federal government, under the Yakama Treaty of 1855 (PDF) it retains the exclusive right to hunt, fish and gather food there.