How did the Germans break the sussex pledge?
The Sussex Pledge was a pact between Germany and the United States in 1916 during World War I. Germany broke the Pledge by resuming unrestricted submarine warfare.
Germany made the Arabic Pledge on September 18, 1915 and followed it with the Sussex Pledge on May 14, 1916. Both related to the sinking of merchant ships carrying US American citizens by German U-Boats during World War I and both expressed an intent by the Germans not to harm American citizens without ample warning.
The Sussex Pledge was made by Germany after the US threatened to cancel diplomatic relations with Germany after Germany sunk a French channel ferry, Sussex, during WWI. The pledge stated that German submarines would not target passenger ships or merchant ships unless the presence of weapons had been established.