The President has plenary Article II, section 2 power to command the armed forces into combat against our enemies.
But a President is very, very unwise to exercise this power if the sitting Congress would refuse a declaration of War.
And I think this "coordinate" view of Our war power (remember, it's Our power we are discussing, the President and the Congress are merely exercising it on Our behalf) is particularly important in the present emergency.
If Congress would defeat a declaration of war now, it is my opinion that the troops should be brought home.
Not because Bush would be required to do so-because he would be unwise to proceed under those conditions.