> No State shall, without the Consent of Congress, lay any Duty of Tonnage, keep Troops, or Ships of War in time of Peace, enter into any Agreement or Compact w

> No State shall, without the Consent of Congress, lay any Duty of Tonnage, keep Troops, or Ships of War in time of Peace, enter into any Agreement or Compact with another State, or with a foreign Power, or engage in War, unless actually invaded, or in such imminent Danger as will not admit of delay. It seems to me that it states “with another State”, as in a capital S State or a member State of the United States. Then explicitly calls out as another option, “or with a foreign power”. Furthermore, the title of Article I, Section 10 of the US Constitution is “Powers Prohibited of States”.