So here's the problem: the (now crumbling) legal wall that was erected in the Nineteenth Century to keep the US military from tyrannizing US citizens is now one more scrap of paper in Alberto Gonzales' trash can for quaint old laws. Its origins are interestingly tainted: the main part of the drive to enact it was because Federal troops were attempting to guard the civil right of universal suffrage in a south that strove to keep blacks away from the polls. But regardless of the bad birth, by and large it has been good that the hand that would unleash US troops on the American citizenry has been restrained.

Now, in The Post-9/11 World Where Everything Has Changed, our administration sees no need to follow this law even pro-forma, by going through the requisite authorization by Congress or declaration of an emergency by the President...they simply put the troops in place, counting on the idea that any subsequent challenge can be cleared by the courts after the fact.

...But what happens, if something happens? Our troops are not trained or equipped to perform in an American city without bringing to it what they brought to Fallujah. Their rifle bullets will pass easily through residential walls; their grenades will kill at a range of several meters. They are trained to eliminate any potential threat during execution of a mission. In contrast, our law enforcement personnel are trained to protect and preserve the lives of the citizens, and to use deadly force only when required.

.....if you look to the past, the citizens of a police state have never ended up better off, or safer. Because once we accept this step, the next will come, and we'll accept that too: maybe dangerous suspects that might have weapons will justify apprehension by the military...then suspicions that a suspect might be hiding in a neighborhood will justify entry and search by the military...then inability to exactly determine a suspect will justify large-scale detention and interrogation by the military.

18 U.S.C. 1385

Sec. 1385. Use of Army and Air Force as posse comitatus

Whoever, except in cases and under circumstances expressly authorized by the Constitution or Act ofCongress, willfully uses any part of the Army or the Air Force as a posse comitatus or otherwise to execute the laws shall be fined under this title or imprisoned not more than two years, or both.

[Updated to delete reference to 13,000 which pertained to the total number of officers doing security)