During the American Revolution and the War of 1812, the young United States faced the overwhelming naval might of the British Royal Navy with only a handful of official warships. To bridge this divide, the Framers included a specific power in Article I, Section 8, Clause 11 of the U. S.
Constitution: the power of Congress to grant 'Letters of Marque and Reprisal.' A Letter of Marque was essentially an official government license that transformed a private civilian vessel into an armed state-sanctioned commerce raider. Shipowners financed their own privateering expeditions in exchange for keeping the profits from captured enemy ships and cargo, which were legally validated by admiralty courts as 'prizes of war.'
This system incentivized private enterprise to disrupt enemy trade routes at zero cost to the federal government. The distinction between a constitutionally sanctioned privateer and an outlaw pirate came down solely to this document. While the Paris Declaration of 1856 largely banned privateering internationally, the United States refused to sign it at the time, desiring to preserve its cheap naval reserve.
Consequently, the Letters of Marque clause remains active in the U. S. Constitution today, prompting occasional modern legislative proposals to use private maritime contractors against modern threats like state-backed piracy or sea-bound drug cartels.