What treaties or legal agreements allow the U.S. be active in a war zone and still claim not to be at war?

by fuzzyferret

I was curious as to how the precident was set following WW2 and during the cold war that a nation could have its own military actively involved in a war zone without having to formally recognize itself as at war with either side.

APOLLOSxxELITE

Because the President can Mobilize military units and call for a deploy of military action. But only Congress can declare war.