Me too! If only the POTUS can call out the National Guard, how are states to defend themselves?
IIRC, governors can call up the NG in their own states only.
The Prez can call up NG from one state and re-alocate them to another state, as he sees fit — with approval of governors, probably.
I remember during Katrina when the press was all over Bush for not sending in the National Guard ... and Bush said he was waiting for a call from the governor.