The text of the London Protocol of 1936 is based, of course, on a declaration which was signed at the London Naval Conference of 1930. The committee of jurists appointed at that time expressed its opinion concerning the greatly disputed definition of a merchant vessel in the report of 3 April 1930:
“The committee wishes to place on record that the expression ‘merchant vessel’ where it is employed in the declaration is not to be understood as including a merchant vessel which is at the moment participating in hostilities in such a manner as to cause her to lose her right to the immunities of a merchant vessel.”
This definition clarifies at least one thing, namely, that by no means every vessel flying a merchant flag may lay claim to being treated as a merchant vessel in the sense of the London Agreement. Beyond this, the explanation has few positive aspects because the question through what kind of participation in hostilities a vessel loses her right to the immunity of a merchant vessel is again subject to the interpretation of the contracting parties. The London Conference, as far as I can see, did not consider this ticklish question any further, and one is probably entitled to assume that this remarkable reserve is based on experiences which the same powers had accumulated in Washington 8 years before.
The Washington Conference of 1922 was held under the impression of the first World War; and therefore it is no wonder that Great Britain, the naval power which during the World War had suffered most from German submarine warfare, now tried to outlaw and abolish altogether by international law submarine warfare against merchant shipping. The resolution, named after the American chief delegate, Root, which in its first part substantially corresponded to the London text of 1930, served that aim. But in the second part the Root Resolution goes further and stipulates that any commander who, no matter whether he acted with or without higher orders, violated the rules established for the sinking of merchant vessels should be punished as a war criminal like a pirate. Finally it was recognized that under the conditions stipulated in the resolution submarine warfare against merchant shipping was impossible, and such warfare was therefore renounced altogether by the contracting powers. The Root Resolution designates these principles as an established part of international law. While it was accepted as such by the delegates, none of the five participating naval powers, U.S.A., Britain, France, Japan, and Italy ratified it.
In connection with the Root Resolution, however, another question was discussed which is of the greatest importance for the interpretation of the London Protocol, namely, the definition of the term “merchantman.” Here the two conflicting views in the entire U-boat question became clearly evident. On the one side there stood Britain, on the other France[[4]], Italy, and Japan, while the United States took the position of a mediator. According to the minutes of the Washington Conference, the Italian delegate, Senator Schanzer, opened the offensive of the weaker naval powers by expressly emphasizing that a merchantman, when regularly armed, might be attacked by a submarine without preliminaries. In a later session Schanzer repeated his statement that the Italian delegation applied the term of “merchantman” in the resolution only to unarmed merchant vessels. He declared this to be in explicit accordance with the existing rules of international law.[[5]]
The French delegate, M. Sarraut, at that time received instructions from his Foreign Minister, M. Briand, to second the reservations of the Italian delegate.[[6]] He thereupon moved to have the Italian reservations included in the minutes of the session.
The Japanese delegate, Hanihara, supported this trend with the statement that he thought it was clear that merchant vessels engaged in giving military assistance to the enemy ceased in fact to be merchant vessels.[[7]] It can therefore be seen that in 1922, three of the five powers represented expressed the opinion that armed merchant vessels were not to be regarded as merchant vessels in the sense of the Agreement.
Since the whole resolution threatened to collapse because of this difference of opinion, a way out was found which is typical of conferences of this kind. Root closed the debate with the statement that in his opinion the resolution held good for all merchant ships as long as the ship remained a merchant vessel.[[8]] With this compromise a formula was created which, while representing a momentary political success, would not however carry any weight in the case of war, for it was left to every participating power to decide whether or not it would grant the armed merchant vessels the protection of the resolution in case of war.
I have described these events of the year 1922 a little more in detail because the powers which took part in them were the same as those which participated in the London Naval Conference of 1930. The London Conference was the continuation of the Washington Conference, and the subjects that had been discussed and included in the minutes of the first conference were of great importance for the second conference. Experts too—and by no means only German but above all American and French experts—based their examinations on the close connection of both conferences, and it was precisely for that reason that they declared the result achieved in the question of submarines to be ambiguous and unsatisfactory. Here I merely wish to point to Wilson’s summarizing report on the London Naval Treaty.[[9]]
This report, besides the ambiguity of the concept “merchant vessel,” also stresses the uncertainty connected with the words “active resistance”; and it is with these very words that an exception from the protection of the merchantman is connected, an exception which likewise is not contained in the actual text of the London Agreement but which nevertheless is generally recognized. I am referring to merchantmen in an enemy convoy. If the London Agreement were interpreted literally, it would be understood that even merchantmen in an enemy convoy must not be attacked without warning but that an attacking warship would have to put the escort vessels out of action first and then stop and search the merchantmen. However, this suggestion, which is impossible from a military point of view, evidently is not made even by the Prosecution. In the report of the British Foreign Office, which has been mentioned several times, it says: