Here is the WaPo article with his extended biography.

And a link to the Willamette University library (named after Sen. Hatfield) bio, which says he was a defender of Indian treaty rights. In this excerpt from Ronald Satz’ monograph on the Chippewa treaty rights fight in Wisconsin, Rep. Hatfield is quoted as labeling the backlash against treaty rights as “racism in all its ugly manifestations.” He also helped to negotiate the Umatilla Basin Project (here).

He introduced legislation to restore the Confederated Tribes of the Siletz Indians of Oregon (here).

Finally, the Hatfield School of Government at Portland State is home to the Institute for Tribal Government.