Answer:
American contribution to WWI forced Germany to go back to Germany. The U.S. were allies with Great Britain, The Ottoman Empire, and the Russian Empire. Germany blew up Great Britain's ship Lucitania. The US was hesitant to join the war, and wanted to stay out of it, because they didn't want to choose a side. After Great Britain intercepted a message from Germany to Mexico telling Mexico to join the war so they can gain land from the US, GB sent it to the US. This and the Lusitania forced the US to join the war. After Russia exited the war Germany finally had a chance to conquer France. Becuase we joined there were fresh forces and money allowing for the Allies to continue the war.