Quote from RCG Trader:
Of course, Lucrum, I take debate in it's classical form, so I use classical rules.
I misspoke about the treaties. This is the source of my claim.
Posse Comitatus Act of of 1878.
A law enacted in 1878 to prohibit the use of the U.S. army in civilian law enforcement, unless otherwise instructed by the president, thereby excluding the military from the civilian sphere. After President Ulysses S. Grant sent a posse comitatus to the polls in the election of 1876, it was presented by Southern Democratic members of the House who resented the use of federal troops during Reconstruction.
I got this from a call from a Texas Rancher off the Glen Beck show who was complaining that they could get no federal help with the drug cartels. Another caller who happened to be in the New Mexico Guard said that they could go, but could only watch. The above Act is the reason.