We already have an "authorization" from Congress to conduct military operations, which to my mind is recognition that we are at war. Ergo, a declaration of war. It does not need to be a declaration of war upon a specific enemy, simply a congressional finding that we are, in fact, at war.
Then which is it - are we already in a state of war as granted by the war powers act, or are we not? You speak from both sides of your mouth.
That is the advantage of speaking out of both sides...
The answer is "both". A finding or declaration of war is legally necessary, for the reasons I have stated. Otherwise, civil and criminal law obtains, and you have to get warrants, etc...
And, in my opinion, Congress has already "recognized" that we are at war, in its authorization for military action after 9/11. So, in my opinion, nothing further is needed. But some may want a more explicit declaration before we continue, and I am ok with that.