[bestintxas]

On a Constitutional basis, nothing usurps the ability of a state to defend itself. See

http://www.americanthinker.com/2010/07/arizonas_constitutional_war_po.html

[reg45]

The Governor of Arizona should recall all members of the Arizona National Guard from Iraq and Afghanistan in order to defend the state from an armed incursion by citizens of a foreign power on the state of Arizona. She should also request that the federal government assist her as required by Article IV Section 4 of the Constitution: "The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against Invasion;"