In January 1917, Kaiser Wilhelm II of Germany declared the resumption of unrestricted submarine warfare, a controversial military strategy employed by the Imperial German Navy. The decision aimed to impede shipping routes to the British Isles and support the ongoing war efforts against the Allies. This announcement marked a significant escalation in tactics as German submarines (U-boats) would target enemy shipping vessels without warning, in direct violation of pre-established maritime guidelines that required submarines to surface and let crews evacuate before sinking a ship.

The move was primarily motivated by the desire to alter the balance of power on the Western Front. German leaders sought to break the British blockade that was severely restricting supplies to Central Powers. By utilizing submarines effectively, they hoped to isolate Britain and France, undermining their capacity to continue the war. This decision was considered risky; while it would exert immediate pressure on the Allies, it also risked drawing the United States into the conflict due to attacks on civilian vessels like the Lusitania in 1915, which had already stirred public opinion against Germany.

Despite the risk, Germany remained steadfast, believing that a successful campaign of unrestricted submarine warfare could end the war swiftly in their favor. This strategy would significantly impact naval warfare and international relations, leading to further Allied advancements and reshaping wartime strategies.