Papers Relating to the Foreign Relations of the United States, 1916, Supplement, The World War

File No. 763.72/2634½

Memorandum on the status of armed merchant vessels, made public April 27, 1916¹

Washington, March 25, 1916 .

I

The status of an armed merchant vessel of a belligerent is to be considered from two points of view: First, from that of a neutral when the vessel enters its ports; and, second, from that of an enemy when the vessel is on the high seas.

First: An Armed Merchant Vessel in Neutral Ports

(1) It is necessary for a neutral government to determine the status of an armed merchant vessel of belligerent nationality which enters its jurisdiction, in order that the government may protect itself from responsibility for the destruction of life and property by permitting its ports to be used as bases of hostile operations by belligerent warships.

(2) If the vessel carries a commission or orders issued by a belligerent government and directing it under penalty to conduct aggressive operations, or if it is conclusively shown to have conducted such operations, it should be regarded and treated as a warship.

(3) If sufficient evidence is wanting, a neutral government, in order to safeguard itself from liability for failure to preserve its neutrality, may reasonably presume from the facts the status of an armed merchant vessel which frequents its waters. There is no settled rule of international law as to the sufficiency of evidence to establish such a presumption. As a result a neutral government must decide for itself the sufficiency of the evidence which it requires to determine the character of the vessel. For the guidance of its port officers and other officials a neutral government may therefore declare a standard of evidence, but such standard may be changed on account of the general conditions of naval warfare or modified on account of the circumstances of a particular case. These changes and modifications may be made at any time during the progress of the war, since the determination of the status of an armed merchant vessel in neutral waters may affect the liability of a neutral government.

Second: An Armed Merchant Vessel on the High Seas

(1) It is necessary for a belligerent warship to determine the status of an armed merchant vessel of an enemy encountered on the high seas, since the rights of life and property of belligerents and neutrals on board the vessel may be impaired if its status is that of an enemy warship.

(2) The determination of warlike character must rest in no case upon presumption but upon conclusive evidence, because the responsibility for the destruction of life and property depends on the actual facts of the case and can not be avoided or lessened by a standard of evidence which a belligerent may announce as creating a presumption of hostile character. On the other hand, to safeguard himself from possible liability for unwarranted destruction of life and property the belligerent should, in the absence of conclusive evidence, act on the presumption that an armed merchantman is of peaceful character.

(3) A presumption based solely on the presence of an armament on a merchant vessel of an enemy is not a sufficient reason for a belligerent to declare it to be a warship and proceed to attack it without regard to the rights of the persons on board. Conclusive evidence of a purpose to use the armament for aggression is essential. Consequently an armament which a neutral government, seeking to perform its neutral duties, may presume to be intended for aggression, might in fact on the high seas be used solely for protection. A neutral government has no opportunity to determine the purpose of an armament on a merchant vessel unless there is evidence in the ship’s papers or other proof as to its previous use, so that the government is justified in substituting an arbitrary rule of presumption in arriving at the status of the merchant vessel. On the other hand, a belligerent warship can on the high seas test by actual experience the purpose of an armament on an enemy merchant vessel, and so determine by direct evidence the status of the vessel.

Summary

The status of an armed merchant vessel as a warship in neutral waters may be determined, in the absence of documentary proof or conclusive evidence of previous aggressive conduct, by presumption derived from all the circumstances of the case.

The status of such vessel as a warship on the high seas must be determined only upon conclusive evidence of aggressive purpose, in the absence of which it is to be presumed that the vessel has a private and peaceable character and it should be so treated by an enemy warship.

In brief, a neutral government may proceed upon the presumption that an armed merchant vessel of belligerent nationality is armed for aggression, while a belligerent should proceed on the presumption that the vessel is armed for protection. Both of these presumptions may be overcome by evidence—the first by secondary or collateral evidence, since the fact to be established is negative in character; the second by primary and direct evidence, since the fact to be established is positive in character.

II

The character of the evidence upon which the status of an armed merchant vessel of belligerent nationality is to be determined when visiting neutral waters and when traversing the high seas having been stated, it is important to consider the rights and duties of neutrals and belligerents as affected by the status of armed merchant vessels in neutral ports and on the high seas.

First: The Relations of Belligerents and Neutrals as Affected by the Status of Armed Merchant Vessels in Neutral Ports

(1) It appears to be the established rule of international law that warships of a belligerent may enter neutral ports and accept limited hospitality there upon condition that they leave, as a rule, within 24 hours after their arrival.

(2) Belligerent warships are also entitled to take on fuel once in three months in ports of a neutral country.

(3) As a mode of enforcing these rules a neutral has the right to cause belligerent warships failing to comply with them, together with their officers and crews, to be interned during the remainder of the war.

(4) Merchantmen of belligerent nationality, armed only for purposes of protection against the enemy, are entitled to enter and leave neutral ports without hindrance in the course of legitimate trade.

(5) Armed merchantmen of belligerent nationality under a commission or orders of their government to use, under penalty, their armament for aggressive purposes, or merchantmen which, without such commission or orders, have used their armaments for aggressive purposes, are not entitled to the same hospitality in neutral ports as peaceable armed merchantmen.

Second: The Relations of Belligerents and Neutrals as Affected by the Status of Armed Merchant Vessels on the High Seas

(1) Innocent neutral property on the high seas can not legally be confiscated, but is subject to inspection by a belligerent. Resistance to inspection removes this immunity and subjects the property to condemnation by a prize court, which is charged with the preservation of the legal rights of the owners of neutral property.

(2) Neutral property engaged in contraband trade, breach of blockade, or unneutral service obtains the character of enemy property and is subject to seizure by a belligerent and condemnation by a prize court.

(3) When hostile and innocent property is mixed, as in the case of a neutral ship carrying a cargo which is entirely or partly contraband, this fact can only be determined by inspection. Such innocent property may be of uncertain character, as it has been frequently held that it is more or less contaminated by association with hostile property. For example, under the Declaration of London (which, so far as the provisions covering this subject are concerned, has been adopted by all the belligerents) the presence of a cargo, which in bulk or value consists of 50 per cent contraband articles, impresses the ship with enemy character and subjects it to seizure and condemnation by a prize court.

(4) Enemy property, including ships and cargoes, is always subject to seizure and condemnation. Any enemy property taken by a belligerent on the high seas is a total loss to the owners. There is no redress in a prize court. The only means of avoiding loss is by flight or successful resistance. Enemy merchant ships have, therefore, the right to arm for the purpose of self-protection.

(5) A belligerent warship is any vessel which, under commission or orders of its government imposing penalties or entitling it to prize money, is armed for the purpose of seeking and capturing or destroying enemy property or hostile neutral property on the seas. The size of the vessel, strength of armament, and its defensive or offensive force are immaterial.

(6) A belligerent warship has, incidental to the right of seizure, the right to visit and search all vessels on the high seas for the purpose of determining the hostile or innocent character of the vessels and their cargoes. If the hostile character of the property is known, however, the belligerent warship may seize the property without exercising the right of visit and search which is solely for the purpose of obtaining knowledge as to the character of the property. The attacking vessel must display its colors before exercising belligerent rights.

(7) When a belligerent warship meets a merchantman on the high seas which is known to be enemy owned and attempts to capture the vessel, the latter may exercise its right of self-protection either by flight or by resistance. The right to capture and the right to prevent capture are recognized as equally justifiable.

(8) The exercise of the right of capture is limited, nevertheless, by certain accepted rules of conduct based on the principles of humanity and regard for innocent property, even if there is definite knowledge that some of the property, cargo as well as the vessel, is of enemy character. As a consequence of these limitations, it has become the established practice for warships to give merchant vessels an opportunity to surrender or submit to visit and search before attempting to seize them by force. The observance of this rule of naval warfare tends to prevent the loss of life of non-combatants and the destruction of innocent neutral property which would result from sudden attack.

(9) If, however, before a summons to surrender is given, a merchantman of belligerent nationality, aware of the approach of an enemy warship, uses its armament to keep the enemy at a distance, or after it has been summoned to surrender it resists or flees, the warship may properly exercise force to compel surrender.

(10) If the merchantman finally surrenders, the belligerent warship may release it or take it into custody. In the case of an enemy merchantman it may be sunk, but only if it is impossible to take it into port, and provided always that the persons on board are put in a place of safety. In the case of a neutral merchantman, the right to sink it in any circumstance is doubtful.

(11) A merchantman entitled to exercise the right of self-protection may do so when certain of attack by an enemy warship, otherwise the exercise of the right would be so restricted as to render it ineffectual. There is a distinct difference, however, between the exercise of the right of self-protection and the act of cruising the seas in an armed vessel for the purpose of attacking enemy naval vessels.

(12) In the event that merchant ships of belligerent nationality are armed and under commission or orders to attack in all circumstances certain classes of enemy naval vessels for the purpose of destroying them, and are entitled to receive prize money for such service from their government or are liable to a penalty for failure to obey the orders given, such merchant ships lose their status as peaceable merchant ships and are to a limited extent incorporated in the naval forces of their government, even though it is not their sole occupation to conduct hostile operations.

(13) A vessel engaged intermittently in commerce and under a commission or orders of its government imposing a penalty, in pursuing and attacking enemy naval craft, possesses a status tainted with a hostile purpose which it can not throw aside or assume at will. It should, therefore, be considered as an armed public vessel and receive the treatment of a warship by an enemy and by neutrals. Any person taking passage on such a vessel can not expect immunity other than that accorded persons who are on board a warship. A private vessel, engaged in seeking enemy naval craft, without such a commission or orders from its government, stands in a relation to the enemy similar to that of a civilian who fires upon the organized military forces of a belligerent, and is entitled to no more considerate treatment.

1. Summarized in circular telegram of this date to Ambassadors and Ministers in European countries and Japan. File No. 763.72/2635a.