Issuing letters of marque presents international legal risks—some real, others imagined—but these are manageable. Further, since a conflict with China might, to paraphrase Dean Acheson, threaten the power, position, and even the existence of the United States, the demands of the conflict would limit the salience of law.1 Such a conflict would result in thousands of U.S. service member deaths and the nearly certain loss of dozens of U.S. Navy ships. The proper frame of reference is spring 1942, when the United States was reeling from the harsh realities of war with Imperial Japan, and not the regional conflicts of the late 20th and early 21st centuries, in which the United States had overwhelming military superiority. A conflict with China would be World War III, not Gulf War III. Military and civilian leaders, as well as the public at large, should judge risks in those terms.

The first risks affect privateers themselves. Under the laws of war and neutrality, warships have rights against arrest and proscription by neutrals. Neutrals might choose not to extend those rights to privateers that want to enter their national waters, for example, to refuel. The United States could mitigate this by using friendly ports, negotiating understandings with neutrals, or pacifying them with other elements of U.S. power.

Critics will call privateers mercenaries, but that would hold no water, legally speaking. The 1977 Additional Protocol I (AP I) of the Geneva Conventions deprived mercenaries of combatant and prisoner-of-war rights, but even under AP I (which the United States has not adopted), privateers cannot be labeled “mercenaries” so long as they are a national of a party to the conflict or a resident of territory controlled by a party to the conflict.

Under both the Second (sick and shipwrecked members of the armed forces at sea) and Third (prisoners of war) Geneva Conventions, privateers are entitled to significant protections. They would be regarded as “members of other militias and members of other volunteer corps” so long as they (1) are commanded by a person responsible for his subordinates, (2) bear fixed distinctive signs recognizable at a distance, (3) carry arms openly, and (4) conduct their operations in accordance with the laws and customs of war.2 These requirements can easily be accommodated.

The other legal hurdle is the myth that the law of naval warfare prohibits U.S. privateering. This confusion arises because some scholars assert that the 1856 Paris Declaration—whose first article banned privateering between the treaty parties—somehow established a customary international prohibition on privateering.3 However, the United States refused to sign the Declaration because it was a bad deal in light of the comparatively small U.S. Navy of the day.4

Some arguments about a customary prohibition are based on the mistaken belief that U.S. acquiescence to the Declaration can be discerned from the United States having contemplated accession during the Civil War or President William McKinley’s 1898 Proclamation 413 during the Spanish-American War.5 However, the United States ultimately chose not to accede.6 Moreover, in an introductory paragraph, Proclamation 413 merely provided that it would be U.S. policy “not to resort to privateering”—implying in this one conflict—“but to adhere to the rules of the [Declaration].” That paragraph also referenced a prior announcement by Secretary of State John Sherman that contemporaneous scholars clearly understood to state that the United States felt legally obligated by the Declaration’s last three articles, but not by the ban on privateering.7

China, and likely other maritime nations, nonetheless will argue that customary international law prohibits privateering. To this, the United States can respond by noting that historical U.S. rejection of the prohibition blocked a general customary prohibition from forming under the doctrine of specially affected states.8 That doctrine assigns greater weight to the practice of states that have a distinctive history of participating in, for example, naval warfare and allows their dissent to block custom formation.9

Even if a general custom has formed, the United States can argue that it has reserved a dormant right to privateer through the persistent objector rule.10 Under this rule, a state is not bound by a custom that it objected to while the custom was emerging. U.S. objection can be found in presidential messages; diplomatic correspondence between 1854 and 1907; and even U.S. law.11

Privateering was again on the chopping block at the Second Hague Conference in 1907. The United States rejected Hague Convention VII (Conversion of Merchant Ships into War-Ships) because, as a U.S. delegate noted, “The United States has not renounced the right to resort to privateering.”12 The formation of customary international law requires relatively consistent state practice done out of a sense of legal obligation, but the absence of U.S. privateering since 1907 has resulted from strategic and policy considerations rather than legal ones.13

Finally, China’s largest shipping company, COSCO, and most of China’s merchant shipping companies are state-owned enterprises (SOEs). The U.S. and foreign publics would likely be more accepting of action against them than privately owned merchant ships. The public also might warm to the idea of privateering if they were to become more aware of China’s maritime militia (see “The South China Sea Needs a COIN Toss,” May 2019, pp. 16–21), which comprises thousands of commercial fishing vessels under the command and control of the Central Military Commission.

But that is all public relations; there is no legally significant difference between an SOE merchant ship and a privately owned merchant ship, so far as privateering would be concerned. All enemy merchant ships—SOE or otherwise—may be captured, and in some cases destroyed, if located outside neutral territory. Further, for the purpose of determining whether any given vessel is a lawful object of attack, both privately owned merchant vessels and SOE vessels are fair game if they constitute a military objective.14