Following the sinking of the British steamship RMS Falaba on March 28, 1915, which resulted in the death of a single American, Leon Thrasher, US President Woodrow Wilson sent an official memorandum to the Germans insisting they discontinue unrestricted submarine war without delay or else diplomatic relations with the US would be severed.
US President Woodrow Wilson wearing knight’s armor sealing a document inscribed: Note an Deutsch unverzug einstell v.d. U-boot Krieg dabbruc – Wilson (“Note: Germans cease submarine warfare immediately. Wilson.”); to right: Justice, naked, only one eye covered, holding scale, from which hangs a sheet of paper on which is indicated 20.April 1915; around: ENTWEDER-ODER (“either, or”).