As the summer of 1916 advanced American contemplation of this agreeable trade relation with blockaded Germany by means of a commercial submarine service was abruptly switched to a review of the manner in which that country was observing its undertaking not to sink unresisting vessels without warning. A certain communication credited to Admiral von Tirpitz was circulated in Germany urging a return to his discarded sea policy. This was nothing more nor less than the pursuit of unrestricted and ruthless submarine warfare, the espousal of which by him as Minister of Marine, in conflict with the milder methods favored by the German Chancellor, forced his resignation earlier in the year. Of course such a change would mean an immediate clash with the United States and the ending of diplomatic relations.
President Wilson had been watching Germany's behavior since May, 1916, when she pledged her submarine commanders to safeguard the lives on board doomed vessels. Three months' probation, according to American reports, failed to show any evidence that she was not living up to her promise; but British reports cited a number of instances pointing to an absolute disregard of her undertaking with the United States. She had hedged this promise with a condition reserving her liberty of action should a "new situation" develop necessitating a change in her sea policy, and the question arose whether she was not trying to create a new situation to justify such a change. Concurrent with the new Von Tirpitz propaganda, at any rate, came a recrudescence of submarine destruction without warning, mainly in the Mediterranean. This activity lent weight to a fear that the kaiser and Von Bethmann-Hollweg were yielding to the pressure exercised by the Von Tirpitz party. Germany regarded her submarines as her chief weapons for damaging the Allies; but she was embarrassed by the problem of how to operate them without clashing with American interests. Her policy at length shaped itself to a careful discrimination in raiding Atlantic traffic and avoiding attacks on liners altogether.
The leader of the German National Liberals, Dr. Ernest Bassermann, echoed the Von Tirpitz cry, in an address to his constituents at Saarbrücken. The most ruthless employment of all weapons, he urged, was imperative. Besides Von Tirpitz, High Admiral Koester, Count Zeppelin, and Prince von Bülow shared this view. He told the world, which he was really addressing, that the submarine campaign had not been abandoned, but only suspended solely on account of the American protest. It was not clear that there had really been any cessation of submarine activity, though some abatement had undoubtedly followed the undertaking with the United States.