The Germans' war on merchant shipping began in less spectacular fashion than their attacks on the Royal Navy. There was no comment at the Admiralty after a British steamer, SS Glitra, went to the ocean bottom on October 20, 1 9 1 4, off the coast of Norway. When the German war on civilian vessels began in earnest in early 1915, it provoked a dangerous political rather than military response. And it came from the world's most important neutral power, the United States. Following the sinking of the British liner Lusitania with a massive loss of civilian life, including 128 Americans, President Woodrow Wilson made it clear that such war measures might bring the United States into the conflict. For the next year and a half, German military authorities kept the submarine war against civilian shipping on a tight chain. The exception was in the Mediterranean, where there were few American vessels to sink. In general, as one naval historian has put it, "As a military weapon the submarine proved itself a far more versatile warship than had been foreseen before the war."