Federal Water rights are allowed to be adjudicated in state courts because Congress’s passage of the McCarren amendment. And as for the vehicular laws, the BLM has a specific provision that says it is illegal to violate state traffic laws. Authority still remains with Congress and can be revoked at any time. Further, any authority not distributed to the state is automatically retained by Congress.
Just to clarify my prior comment - “Nevada state laws do not restrict how the US Government run’s it’s own land.” Your interpretation of what I said, while plausible, was not in keeping with the spirit of the conversation.
I will give you an example from Leavenworth, KS. The fort was in existence before the state. The land on the fort is US Government land. Technically, no police officer of the state can enter Ft Leavenworth with permission of the Provost Marshal. In fact, violations of law (even traffic violations) are not resolved in city or county court. They are resolved the US Magistrate court due to this separation. I know, I got a parking ticket.
The State of Kansas can make all the laws that they want about how the land is to be used but they do not have any means of enforcement without that agreement. While there may be agreements in place, they do not carry the weight of law.
In my world, the federal government has to prove beyond a reasonable doubt that they're not lying about anything they're involved in, since that's all they ever do.
My assumption in this case is that they changed the rules after the fact, and are lying about it.