During 1917, there were two major events determining the end of the war. First Germany announced unrestricted submarine warfare leading to U.S. entry on the side of the allies,. Second the communist takeover of Russia, leading to an end of its war against Germany. What if Germany had not started unrestricted submarine warfare, leaving U.S. to remain neutral? The collapse of Russia would have allowed Germany to greatly strengthen the western front without reinforcements for the allies by American troops. In addition, German occupation of Ukraine would have mitigated food shortages of Germany by using Ukraine harvest. As a minimum, Germany and Austria would have been able to fight on much longer.