Although President Wilson formally severed diplomatic relations in February 1917, upon the resumption of all-out submarine warfare, he was still unclear of the extent of public support. He then refused to ask Congress for a declaration of war, arguing that Germany had still not committed “real apparent acts” justifying a military reaction. During the summer summer, the German Navy formed a force of four submarines in Cattaro for operations against trade in the Mediterranean. The campaign began in October 1915, when U-33 and U-39, later followed by U-35, were ordered to attack the approximations with Thessaloniki and Kavalla. This month, 18 ships were sunk, for a total of 63,848 tons. In the same month, it was decided that further reinforcements were needed and that another large submarine, U-38, was sailing towards Cattaro. As Germany was not yet at war with Italy, although Austria had been, German submarines were ordered to refrain from any attack on Italian shipping in the eastern Mediterranean, where the Italians could only expect hostile actions from German submarines. During an operation to the west, up to the line of Cape Matapan, German submarines flying the flag of Austria and a policy of immersion was carried out without warning, as large merchant ships could be attacked under the suspicion of being vans or auxiliary cruisers. On 18 February 2, 1915, German Admiral Hugo von Pohl declared the waters surrounding the British Isles a war zone and warned that any Allied commercial ship found in the war zone would be destroyed, while indicating that it would not always be possible to avoid endangering the ship`s crew and passengers; M. Pohl also said neutral ships were also under threat, given that Britain has recently abused neutral flags to describe its ships.
On 7 May 1915, RMS Lusitania was submerged by the Imperial Navy submarine U-20 off the south coast of Ireland; Of the 1,962 passengers and crew on board, 1,198 people died, including 128 U.S. citizens. Immediately after the sinking, German actors in the United States began to justify the actions of U-20 and dissuade the United States from going to war. If we look at the German defense of the Lusitania immersion, we can see how the German Empire made legal arrangements to defend the practice of submarine warfare without restriction in general. The day after the fall of the Lusitania, Dr. Bernhard Dernburg – the former German colonial secretary – made a statement in Cleveland, on behalf of the German Empire, which was later published in the New York Times. . . .