During WWI, in my opinion, the thing that might have been the reason for America's success was the use of this poster.  This poster is, obviously, about purchasing war bonds.  War bonds were used throughout the war to supply and provide for the troops overseas.  As you can see in this picture, the black swastika is overshadowing, what looks like. patriotic, American children.  This symbolizes that the Nazi power is getting closer and closer to American soil.  Furthermore, this poster is telling the public that if we purchase war bonds then we could be saving these children's lives because we would be contributing to the American war effort.