From your link
SUBCHAPTER H. CALLING OF FORCES
Sec. 431.111. CALLING OF FORCES BY GOVERNOR. (a) The governor may call all or part of the state military forces to repel or suppress an invasion of or insurrection in or threatened invasion of or insurrection in the state or if the governor considers it necessary to enforce state law. If the number of state military forces is insufficient, the governor shall call the part of the reserve militia that the governor considers necessary.
(b) The governor may call all or part of the state military forces to assist civil authorities in guarding prisoners, conveying prisoners within the state, or executing law as the public interest or safety requires.
(c) The governor may order a commander of a unit of the state military forces to appear at a time and place directed to suppress or prevent tumult, riot, or the actions of a group of persons acting together by force with intent to commit a breach of the peace or violence to a person or property or to otherwise violate state law.
well, then. Suppress and Invasion. That just about covers it. Defend your state Gov. Perry!
in doing so, defend our nation.
Looks pretty cut and dry to me...
Now if you can pay for it...That’s the big deal there...