The convoy system proved to be the cure for the submarine threat. By the end of 1917 submarine sinkings had plummeted from their April peak and would never again reach Holtzendorff's key figure of 600,000 tons per month. According to the logic behind the Pless decision, Germany had played its last card and failed. In theory the time had come to seek an end to the war; however, there were two compelling reasons for the Germans to continue. First, the Bolshevik Revolution and Russia's consequent withdrawal from the war appeared to shift the balance of power in Germany's favor. To the responsible leaders within Germany, especially General Ludendorff, this seemed to make possible the playing of a new [last card,] a final, major offensive in the west that would drive Britain and France out of the war before the rising flood of American soldiers irrevocably turned the tide.
The other reason for the continuation of the war was the desire to achieve the remainder of Germany's war aims. The Treaty of Brest-Litovsk allowed Germany to attain her aims in the east, and all that now remained was to complete the reorientation of Europe toward Germany by achieving total victory in the west.1 This was particularly important for the German navy. Germany's aims in the east were primarily those of the army; the navy's aims were concentrated in the west and remained as yet unfulfilled.2