Primary Documents - U.S. Ultimatum to Germany Regarding Unrestricted U-Boat Warfare, 18 April 1916

Photograph of U.S. President Woodrow Wilson Reproduced below is the text of U.S. President Woodrow Wilson's ultimatum to the German government regarding the latter's use of U-boats.

In his ultimatum, dated 18 April 1916, Wilson condemned Germany's policy of unrestricted submarine warfare, which resulted in merchant vessels being sunk without warning should they be suspected of trading with the Allies.

Wilson warned that the U.S. would not tolerate the continuation of such a policy and demanded it be revoked by the German government (a stance re-iterated in a speech to Congress the following day).

Wilson had been spurred into action by the sinking of the British passenger ship Sussex while it was in the English Channel.  Several U.S. citizens were among those drowned.  Germany initially denied sinking the Sussex but subsequently admitted doing so.

Alarmed by the U.S. stance the German government - in the form of Foreign Minister Gottlieb von Jagow - withdrew its policy, noting that in future a clear warning would be given before ships were torpedoed.  The Naval Minister, Alfred von Tirpitz, was furious, and later attributed Germany's wartime defeat to its weakness at this time in the face of U.S. opposition.

Germany's reintroduction of the policy in February 1917 led to the U.S. breaking off diplomatic relations with Germany.

President Wilson's Ultimatum to German's Foreign Minister Regarding Use of U-Boats, 18 April 1916

Information now in the possession of the Government of the United States fully establishes the facts in the case of the Sussex, and the inferences which the Government has drawn from that information it regards as confirmed by the circumstances set forth in your Excellency's note of the 10th inst.

On the 24th of March, 1916, at about 2.50 o'clock in the afternoon, the unarmed steamer Sussex, with 325 or more passengers on board, among whom were a number of American citizens, was torpedoed while crossing from Folkestone to Dieppe.

The Sussex had never been armed; was a vessel known to be habitually used only for the conveyance of passengers across the English Channel; and was not following the route taken by troop ships or supply ships.  About eighty of her passengers, non-combatants of all ages and sexes, including citizens of the United States, were killed or injured.

A careful, detailed, and scrupulously impartial investigation by naval and military officers of the United States has conclusively established the fact that the Sussex was torpedoed without warning or summons to surrender, and that the torpedo by which she was struck was of German manufacture.

In the view of the Government of the United States these facts from the first made the conclusion that the torpedo was fired by a German submarine unavoidable.  It now considers that conclusion substantiated by the statements of Your Excellency's note.  A full statement of the facts upon which the Government of the United States has based its conclusion, is enclosed.

The Government of the United States, after having given careful consideration to the note of the Imperial Government of the 10th of April, regrets to state that the impression made upon it by the statements and proposals contained in that note is that the Imperial Government has failed to appreciate the gravity of the situation which has resulted, not alone from the attack on the Sussex, but from the whole method and character of submarine warfare as disclosed by the unrestrained practice of the commanders of German undersea craft during the past twelve-month and more in the indiscriminate destruction of merchant vessels of all sorts, nationalities, and destinations.

If the sinking of the Sussex had been an isolated case the Government of the United States might find it possible to hope that the officer who was responsible for that act had wilfully violated his orders or had been criminally negligent in taking none of the precautions they prescribed, and that the ends of justice might be satisfied by imposing upon him an adequate punishment, coupled with a formal disavowal of the act and payment of a suitable indemnity by the Imperial Government.

But, though the attack upon the Sussex was manifestly indefensible and caused a loss of life so tragical as to make it stand forth as one of the most terrible examples of the inhumanity of submarine warfare as the commanders of German vessels are conducting it, it unhappily does not stand alone.

On the contrary, the Government of the United States is forced by recent events to conclude that it is only one instance, even though one of the most extreme and most distressing instances, of the deliberate method and spirit of indiscriminate destruction of merchant vessels of all sorts, nationalities, and destinations which have become more and more unmistakable as the activity of German undersea vessels of war has in recent months been quickened and extended.

The Imperial Government will recall that when, in February, 1915, it announced its intention of treating the waters surrounding Great Britain and Ireland as embraced within the seat of war and of destroying all merchant ships owned by its enemies that might be found within that zone of danger, and warned all vessels, neutral as well as belligerent, to keep out of the waters thus proscribed or to enter them at their peril, the Government of the United States earnestly protested.

It took the position that such a policy could not be pursued without constant gross and palpable violations of the accepted law of nations, particularly if submarine craft were to be employed as its instruments, inasmuch as the rules prescribed by that law, rules founded on the principles of humanity and established for the protection of the lives of non-combatants at sea, could not in the nature of the case be observed by such vessels.

It based its protest on the ground that persons of neutral nationality and vessels of neutral ownership would be exposed to extreme and intolerable risks, and that no right to close any part of the high seas could lawfully be asserted by the Imperial Government in the circumstances then existing.

The law of nations in these matters, upon which the Government of the United States based that protest, is not of recent origin or founded upon merely arbitrary principles set up by convention.  It is based, on the contrary, upon manifest principles of humanity and has long been established with the approval and by the express assent of all civilized nations.

The Imperial Government, notwithstanding, persisted in carrying out the policy announced, expressing the hope that the dangers involved, at any rate to neutral vessels, would be reduced to a minimum by the instructions which it had issued to the commanders of its submarines, and assuring the Government of the United States that it would take every possible precaution both to respect the rights of neutrals and to safeguard the lives of non-combatants.

In pursuance of this policy of submarine warfare against the commerce of its adversaries, thus announced and thus entered upon in despite of the solemn protest of the Government of the United States, the commanders of the Imperial Government's undersea vessels have carried on practices of such ruthless destruction, which have made it more and more evident as the months have gone by that the Imperial Government has found it impracticable to put any such restraints upon them as it had hoped and promised to put.

Again and again the Imperial Government has given its solemn assurances to the Government of the United States that at least passenger ships would not be thus dealt with, and yet it has repeatedly permitted its undersea commanders to disregard those assurances with entire impunity.

As recently as February last it gave notice that it would regard all armed merchantmen owned by its enemies as part of the armed naval forces of its adversaries and deal with them as with men-of-war, thus, at least by implication, pledging itself to give warning to vessels which were not armed and to accord security of life to their passengers and crews; but even this limitation their submarine commanders have recklessly ignored.

Vessels of neutral ownership, even vessels of neutral ownership bound from neutral port to neutral port, have been destroyed, along with vessels of belligerent ownership, in constantly increasing numbers.  Sometimes the merchantmen attacked have been warned and summoned to surrender before being fired on or torpedoed; sometimes their passengers and crews have been vouchsafed the poor security of being allowed to take to the ship's boats before the ship was sent to the bottom.

But again and again no warning has been given, no escape even to the ship's boats allowed to those on board. Great liners like the Lusitania and Arabic, and mere passenger boats like the Sussex, have been attacked without a moment's warning, often before they have even become aware that they were in the presence of an armed ship of the enemy, and the lives of non-combatants, passengers and crew, have been destroyed wholesale and in a manner which the Government of the United States cannot but regard as wanton and without the slightest colour of justification.

No limit of any kind has, in fact, been set to their indiscriminate pursuit and destruction of merchantmen of all kinds and nationalities within the waters which the Imperial Government has chosen to designate as lying within the seat of war.  The roll of Americans who have lost their lives upon ships thus attacked and destroyed has grown month by month until the ominous toll has mounted into the hundreds.

The Government of the United States has been very patient. At every stage of this distressing experience of tragedy after tragedy it has sought to be governed by the most thoughtful consideration of the extraordinary circumstances of an unprecedented war and to be guided by sentiments of very genuine friendship for the people and Government of Germany.

It has accepted the successive explanations and assurances of the Imperial Government as, of course, given in entire sincerity and good faith, and has hoped, even against hope, that it would prove to be possible for the Imperial Government so to order and control the acts of its naval commanders as to square its policy with the recognized principles of humanity as embodied in the law of nations.  It has made every allowance for unprecedented conditions and has been willing to wait until the facts became unmistakable and were susceptible of only one interpretation.

It now owes it to a just regard for its own rights to say to the Imperial Government that that time has come.  It has become painfully evident to it that the position which it took at the very outset is inevitable, namely, the use of submarines for the destruction of an enemy's commerce, is, of necessity, because of the very character of the vessels employed and the very methods of attack which their employment of course involves, utterly incompatible with the principles of humanity, the long-established and incontrovertible rights of neutrals, and the sacred immunities of non-combatants.

If it is still the purpose of the Imperial Government to prosecute relentless and indiscriminate warfare against vessels of commerce by the use of submarines, without regard to what the Government of the United States must consider the sacred and indisputable rules of international law and the universally recognized dictates of humanity, the Government of the United States is at last forced to the conclusion that there is but one course it can pursue.

Unless the Imperial Government should now immediately declare and effect an abandonment of its present methods of submarine warfare against passenger and freight-carrying vessels, the Government of the United States can have no choice but to sever diplomatic relations with the German Empire altogether.

This action the Government of the United States contemplates with the greatest reluctance, but feels constrained to take in behalf of humanity and the rights of neutral nations.

Source: Source Records of the Great War, Vol. IV, ed. Charles F. Horne, National Alumni 1923

A "listening post" was an advanced post, usually in no-man's land, where soldiers tried to find out information about the enemy.

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