You make my point for me A state of war has not been declared! The Constitution of the US is still in effect, unless somethings changed while I wasn't looking. Artcle 1 Sec 8 gives the Congress the power to declare a war, which they have not!
We are at war, whether you like it or not.
Whether it is declared or not, we are attacking the military and political structures of another nation with our military might. We might say we are not "at war with Afghanistan," but we quite plainly are.
Under your definition, we were not at war with Iraq in 1991. Nor over Kosovo in 1999.
This war is being prosecuted under the same rubric - a resolution by the Congress authorizing the President to use military force.
Besides, if Congress had issued a declaration of war, would you then be in favor of nuclear retaliation for the introduction of biological warfare?