763.72/2351a

The Secretary of State to President Wilson

My Dear Mr. President: The enclosed copies of telegrams5 telling of the sinking of the British steamship Persia on December 30th about three hundred miles northwest of Alexandria do not, in my opinion, seriously affect the Ancona case, since the evidence of torpedoing is inconclusive, the nationality of the submarine, if one was the cause, is unknown, and it is stated that the Persia carried an armament.

The fact that the vessel was carrying a 4.7 gun raises a question which, it seems to me, we ought to settle.

Three or four days ago I forwarded to the Italian Ambassador at his request the statement in regard to armed merchant vessels, which we issued in September, 1914.6 I had discussed the question some four or five weeks before with Mr. Barclay of the British Embassy and told him that, in view of the development of submarines as commerce destroyers, which had been unknown when our statement was issued, I felt that the arming of merchant vessels with any gun, of sufficient calibre to attack a submarine, would make it very difficult, if not impossible, to insist that a submarine should expose itself to attack by coming to the surface and hailing a vessel so armed; and that, while the armament might be termed “defensive”, it was capable of being used offensively against a submarine and so, I thought, that a merchant ship carrying a gun or guns would have to be considered and treated as a vessel of war if it entered our ports.

In view of this opinion, which I believe I stated to you orally some time ago, I wrote the Italian Ambassador a letter enclosing the statement of September, 1914, explaining the change of view which the new conditions had forced upon us. I enclose a copy of that letter7 with our printed statement as to the status of armed merchant vessels.

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Since we issued the statement of September, 1914, formally, it appears to me advisable to issue a new statement setting forth the new conditions resulting from the successful employment of submarines in interrupting and destroying commercial vessels, the impossibility of a submarine’s communicating with an armed merchant ship without exposing itself to the gravest danger of being sunk by gunfire because of its weakness defensively, the unreasonableness of requiring a submarine to run the danger of being almost certainly destroyed by giving warning to a vessel carrying an armament, and that, therefore, merchant vessels should refrain from mounting guns large enough to sink a submarine, and that, if they do, they become vessels of war and liable to treatment as such by both belligerents and neutrals.

The chief difficulty with the situation seems to me to lie in this: If some merchant vessels carry arms and others do not, how can a submarine determine this fact without exposing itself to great risk of being sunk? Unless the Entente Allies positively agree not to arm any of their merchant vessels and notify the Central Powers to that effect, is there not strong reason why a submarine should not warn a vessel before launching an attack?

You will recall the case of the Baralong where a German submarine was bombarding a vessel from which the crew had escaped in boats, when a tramp steamer approached flying the American flag. The submarine remained on the surface and awaited the steamer, which on nearing the submarine lowered the American flag, hoisted the British colors, and with a gun mounted on the stern (a defensive armament according to our early definition) opened fire and sank the German vessel killing all the crew. The British Government would urge that this was merely a ruse de guerre and entirely allowable, and so it would have been under old conditions, but under the new conditions it presents a strong argument in favor of submarine attack without warning.

Not only, therefore, should we, in my judgment, rewrite our statement as to the status of armed merchant vessels but show that if any vessels of that class is armed, all merchant vessels are in danger of sudden attack without warning. As to the use of the American flag on any merchant ship converted into an armed vessel it might be well also to make representations to the British Government.

In view of the sinking of the Persia it would seem to be opportune and advisable to act in this matter, if it is decided to act, as expeditiously as possible.

Faithfully yours,

Robert Lansing
  1. Not printed; for correspondence previously printed concerning the Persia case, see Foreign Relations, 1916, supp., pp. 143156, passim, and p. 214.
  2. Ibid., 1914, supp., p. 611.
  3. Ibid., 1916, supp., p. 749.