I still cannot locate the provision in the US CONSTITUTION that authorizes the Federal Government to be involved in a Free, Independent, Sovereign State, unless of course they are claiming Treason, Piracy or Counterfeiting. All it takes is for the Legislature to immediately revoke ALL Agreements, Contracts and Permissions granted to the Federal Government authorizing their presence in the State.
They can also get involved if citizen’s rights are being violated which has been known to happen at the state level. (Of course the Feds have a history of that as well)
Of course a state can try that route and what you have is an attempt at secession.