The dramatic rise in shipping losses due to the increased presence of German submarines (as foretold in the Zimmerman telegram) had made the American population sit up and take notice in a way that the war had never done before. The attached four notices were printed on the front pages of an Atlanta paper one month prior to the U.S. Congress' declaration of war; each one pertains to military recruiting or the need for military equipment.
The widening of hostilities also served to outrage the Latin American republics: Guatemala would soon break off all relations with Germany and Brazil would declare war in October of that year.
Click here to read about the new rules for warfare that were written as a result of the First World War - none of them pertain to the use of poison gas or submarines.
