Your link to the Congressional Declaration Of War, please?
Bush saying he declares War Against Terrorism carries as much constitutional weight as me saying I declare War Against My Expanding Waistline, except he gets to send planes and bombs and troops out there, outside of his Constitutional Authority, and I have to make do with grilled chicken.
Interesting that you don't trust 'em with anything else, except the full might of our armed forces. Don't quite know what to make of that...
Would Alexander Hamilton be an acceptable authority for you?