Presidential Wars With No Congressional Declarations
Under the definitions of war and co-belligerency referenced above, the United States is fighting nine known presidential wars with no congressional declarations in violation of the Declare War Clause. In none of these conflicts has Congress declared war or otherwise by statute or joint resolution made a decision to change the condition of the nation from a state of peace to war.
At present, the United States is at war with ISIS—a non-state actor—everywhere in the world. Congress has never enacted a declaration of war against ISIS. The President acted unilaterally. The United States military is operating under the laws of war in fighting ISIS.