Privatizing national security: I'm against it, but the Founders loved it
Article I, Section 8:
To declare War, grant Letters of Marque and Reprisal, and make Rules concerning Captures on Land and Water;
To raise and support Armies, but no Appropriation of Money to that Use shall be for a longer Term than two Years;
To provide and maintain a Navy;
Letters of Marque and Reprisal are listed before even the national Army and Navy. And Jefferson preferred them to having a Navy at all.
Letters of Marque and Reprisal were licenses from Congress to privateers, the Blackwater of its day: ship owners would fit out their ships as private men-of-war and attempt to sink, or preferably capture, enemy warships and merchants. If they sank them, they got a small payment; if they captured them, they got to keep most of the proceeds of the ships and cargo. This could be quite a bit of money.
And who were some of the biggest outfitters of privateers in the early days? The same New England shippers who revolted when the Crown favored the East India Company with its taxes. Names like Hancock.
Anyways, privateering ran out of fashion about the time of the Civil War, but privatizing war is specifically sanctioned in the Constitution.