Quinn the Eskimo (WWI Harley)

Good question. The war was about treaties. Austria's arch-duke was killed by Germans, and many countires either agreed to support Austria or German before had. Basically, the U.S. was slow to act, but when our ability to trade with England was threatened we joined the war too. It reminds me of the Seven Year War on a more global scale. You have my back, and I have your back, so we both must go to war because of these agreements.