"If I'm not mistaken, doesn't that document leave this sort of thing in the hands of the individual states? What was that thing called, again?"
Actually, the Constitution does not leave this in the hands of the states. The Posse Comitatus Act is not a part of the Constitution. Just as it was constitutional for Congress to pass this law in the late 1800s, it is just as constitutional for them to amend or rescind this act.
I think this is a smart move for President Bush. He knows that the congress will never give him that power. NEVER. But with all the MSM and Democrats bitchin about too slow, too fast, the president knows they will blame him no matter what he does. So, he says, If you're going to blame me, then give me the power. (knowing congress won't) then he can say. How can you blame me for being too slow, too fast, but you do not give me the power. I don't have the power now and you won't give me the power. Now, Sit down and shut up!
Congress passed the law for good and prudent reason, seeing the abuses caused by having the military acting as law enforcement during the Reconstruction period. The American Revolution was partly caused by British troops trying to act in a law enforcement capacity
The frame of mind that makes for a good soldier generally makes for a bad cop. Something to keep in mind as our police forces become increasingly militarized