Here are the briefs relevant to the sovereign immunity issue in Deschutes River Alliance v. Portland General Electric Company:
Final Tribal Amici Brief in Support of Warm Springs – File-Stamped
Second Brief on Cross-Appeal – CTWS (filed 9 28 20)
And here are the lower court materials in Deschutes River Alliance v. Portland General Electric Company (D. Or.):
72 Warm Springs Motion to Dismiss
74 Pacific Gas Motion to Dismiss