I had service prior to my appointment as a Chaplain. I suspect I know the same as many and more than some. Obviously, many others have knowledge and experience greater than my own.
The Constitution authorizes at least 3 levels of direct offensive military operations against an enemy:
War
Letter of Marque (selected targets)
Letter of Reprisal (retribution)
The Constitution also provides other openings for offensive operations:
a. provide for the common defense (a wide open door, because it is as Congress sees fit to accomplish the same.)
b. To define and punish Piracies and Felonies committed on the high Seas, and Offenses against the Law of Nations;
c. make Rules concerning Captures on Land and Water
d. To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions;