In the absence of a declaration of war, in any case in which United States Armed Forces are introduced—It's the setting forth of the requirement in Part (B) that will be interesting to read.
(1) into hostilities or into situations where imminent involvement in hostilities is clearly indicated by the circumstances;
(2) into the territory, airspace or waters of a foreign nation, while equipped for combat, except for deployments which relate solely to supply, replacement, repair, or training of such forces; or
(3) in numbers which substantially enlarge United States Armed Forces equipped for combat already located in a foreign nation;
the President shall submit within 48 hours to the Speaker of the House of Representatives and to the President pro tempore of the Senate a report, in writing, setting forth—
(A) the circumstances necessitating the introduction of United States Armed Forces;
(B) the constitutional and legislative authority under which such introduction took place; and
(C) the estimated scope and duration of the hostilities or involvement.
Thank you...