There is no need. The Congress has already authorized the President to make that war -- against the terrorists and states that harbor them. Legally, the 9/11 resolution carried the force of a declaration of war. No further legislative action is necessary.
Though a little bi-partisan support for the war effort would certainly be welcome...
Understood.
BUT - a formal declaration of War would allow emergency powers specifically excluded from the resolution passed by Congress. (including elements of the sedition act!)