I agree with you, but some other things have to be done first. When I was a student at the Armed Forces Staff College, during the Vietnam whatever-it-was, one of our speakers was a high Department of Defense official. He was asked, during the question period, why the US hadn't declared war in Vietnam. His reply was that there was a whole host of laws that came into effect with a declaration of war, and the Administration didn't want to invoke those laws (things like government allocation of scarce materials, control of transportation, etc.). Those laws need to be repealed, so they don't automatically come into effect with a declaration of war.
The instructor was winging it. The Host of Laws may come into effect if the FedGov wishes. Nothing is automatic, not even a Host of Laws including national speed limit, which we can have anyway, or rationing, which we can have anyway, or the draft, which we can have anyway. FedGov control over factory production such as tanks, airplanes, and ships instead of Chevys and Fords is the biggie, and they don't even have to invoke that.