Here is the opinion in Jamul Action Committee v. Chaudhuri.

The court’s syllabus:

The panel affirmed the district court’s denial of a petition for a writ of mandamus under the Administrative Procedure Act of a group of tribal members and organizations, alleging that the National Indian Gaming Commission violated the National Environmental Policy Act when it approved the Jamul Indian Village’s gaming ordinance for a casino in Jamul, California, without first conducting a NEPA environmental review. The district court held that the Gaming Commission’s approval of the 2013 gaming ordinance was not “major federal action” within the meaning of NEPA requiring the preparation of an environmental impact statement. Affirming on different grounds than the district court, the panel held that even if the GamingCommission’s approval of the gaming ordinance was a major federal action within the meaning of NEPA, the GamingCommission was not required to prepare an environmental impact statement because there was an irreconcilable statutory conflict between NEPA and the Indian Gaming Regulatory Act, pursuant to San Luis & Delta-Mendota Water Auth. v. Jewell, 747 F.3d 581, 648 (9th Cir. 2014) (holding that an agency need not adhere to NEPA “where doing so ‘would create an irreconcilable and fundamental conflict’ with the substantive statute at issue”).

Briefs here.