Where did you get that idea? National Guard are dual hatted as state organized militia, and federal reserve. Each officer has to have "federal recognition". Guardsmen carry the same ID as federal reserve members. They are just as required to deploy overseas when activated as federal reservists, since they *are* federal reservists, and as active duty members.
How do I know? I was one, in between being a "pure" federal reservist, and following being an active duty member.
'Course it was a looong time ago, but those rules haven't changed.
I thought the main purpose of the National Guard is for home duty. I know they are obligated to serve as directed, as needed.
I think it odd that Marine reservists ready-to-go stay home their entire five year hitch, and National Guard troops were being returned repeatedly to the Middle East.