But...when the tribes challenged their rights for 50% allocation against WA state, the Boldt suit was titled "United States v Washington". Since the US federal government is responsible for enforcing the tribal treaty rights, and the tribes sued the federal government for negligence, it would be "United States v United States."
The tribes love beating up the state bankroll on the feds dime. We pay both sides when we sue ourselves on behalf of the tribal rights. Sadly, sometimes it's rightly so, sometimes not.