The content is a hash of warmed-over "sovereign citizen" tax-protester crap from the '80s & '90s. His message is the illogical evolution of the Posse Comitatus Movement of that era.
The more violent members of the movement got dead or were imprisoned. There have been multitudinous cases where the revisionist myth has been used as a legal defense and it has been roundly struck down.
Apparently the letters to the state governors is just another development of the fallacious legalese used by these fringe malcontents to pester the various government bodies, to be added to the attempted "citizen arrests", false liens and bogus litigation they've mounted in the past.
I'm a little surprised I didn't recognize the same tactics as they've been used by the Birther Movement, most especially Orly Taitz.
I'm also chuckling as I realize that the lunatic "Tea Partiers" (nee Baggers)have been sucked in by these charlatans. They've been most careful not to use certain jargon (such as Admiralty Law) in the TP "literature", but if it wasn't clear before that Palin et al have been sucked in by this crowd, Joshua has announced it by linking the "Oath Keepers", the "Tea Party", and the bogus "Guardians of the Republic".
http://en.wikipedia.org/wiki/Sovereign_citizen_movement It's too early to be sure of the vector, but clearly the TPs have been infected.
It should be noted that, although these loquatious loons are most comical in their convoluted legal theorizing, there is a hardrock core of violence that has always been attached to them. I don't think the ultimatum to the governors is more than grandiose posturing, but I'll be very surprised if there is not some real violence attached to some of the activities of these "movements" in the very near future.