In late 1916, with the tide of the war turning against them, and the British blockade of Germany having caused severe shortages of food, fuel, and war materiel, the Germans decided to reinstitute unrestricted submarine warfare, which became effective on February 1, 1917. Two days later, in response to the new submarine campaign, US President Woodrow Wilson severed all diplomatic relations with Germany (cf. no. 70), an act that precipitated the US Declaration of War on April 6, 1917.
Drowning Englishman reaching for a life-preserver on which: AMERIKA; within curve at top: 3·FEBRVAR·1917