The National Guard origins are slightly different. They are essentially state-run militia. They are belong to their respective states. Their state can call up the national guard in times of emergency. IIRC their funding and training is also provided for by the state.
However, they are also Federal, and serves the nation in time of war.
Singer high
Talking about USMC books, here's one I just bought from Kino. Quite up-to-date.