If tribes want to be independent from the United States and not pay taxes or be under our laws then make a federal law that going there means you have to have a passport, like Canada.
To visit these Indian Nations will mean going through border crossings, and U.S. Customs & Indian Customs.
And those who live there will also be required to carry their own form of passport from their Indian Nation.
Then our taxpayers who visit will have to pass through border crossings, and make items bought there taxable by U.S. Customs, and same for the residents returning to their nation.
Then less U.S. citizens will go and spend money at Indian Nations, and then make casinos legal everywhere.
Then tax can be collected from WA residents because it is no longer on Indian Nations, and people will decide to use WA state casinos.