In a warm, overstuffed auditorium at the University of Colorado on Thursday, tribal representatives from around the Colorado River Basin had a message for their federal and state counterparts: Tribes won’t be cut out of key water talks that will decide the future of the basin.

“As we develop a post-2026 plan, it’s no longer acceptable for the U.S. to meet with seven basin states separately, and then come to basin tribes, after the fact, with a post-hoc explanation or rationalization of what was discussed, or even worse, what was decided,” said Gov. Stephen Roe Lewis of the Gila River Indian Community in Arizona.