The federal executive has no authority over the Texas State Guard.
The federal executive has no authority over the Texas reserve militia.
The federal executive does have authority over the Texas Army National Guard and the Texas Air National Guard only when they are called into actual service of the United States. At all other times the Governor is the Commander in Chief of these forces.
Tex. Gov. Code Sec. 431.071
http://www.statutes.legis.state.tx.us/Docs/GV/htm/GV.431.htm#431.071
Tex. Gov. Code Sec. 431.001
http://www.statutes.legis.state.tx.us/Docs/GV/htm/GV.431.htm#431.001
Tex. Const. art. 4, § 7
http://www.statutes.legis.state.tx.us/Docs/CN/htm/CN.4.htm#4.7
Well,first of all...I weighed in on this subject by responding to the post "National Guard".I never knew that a Texas *state* guard even existed until I saw it mentioned in this thread.
Second of all...I'd bet the clothes on my back that Osama Obama's Mini Me,Attorney Corporal Holder,could shut the State Guard down in about 30 seconds if they started "patrolling" the border.Mind you.I'm not saying that he'd have the *Constitutional authority* to do so...just that he'd be *able* to do so.