As Madison put it- defending the legislature's war powers, ironically:
"A declaration that there shall be war, is not an execution of laws: it does not suppose pre-existing laws to be executed: it is not, in any respect, an act merely executive. It is, on the contrary, one of the most deliberate acts that can be performed; and when performed, has the effect of repealing all the laws operating in a state of peace, so far as they are inconsistent with a state of war; and of enacting, as a rule for the executive, a new code adapted to the relation between the society and its foreign enemy. In like manner, a conclusion of peace annuls all the laws peculiar to a state of war, and revives the general laws incident to a state of peace."
I think Bush has already won on this. The outrage is based upon a strawman--Bush is intercepting calls between US citizens. The fact is that he's not. He's intercepting calls between people in the US, and al Qaeda operatives. Frame the question in that way, and he wins every time.
The only people who argue otherwise are the partisans and the fools, of which there are many, but not enough to sway the day.