The Americans didn't join the war because the government was afraid of the German population in the States would support and revolt.The Germans used their U boats to stop the Americans from sending supplies to the British Empire. May 7 1915 The Germans sunk a civilian ship that had american passengers on it. January 1917 The Germans sent Mexico the Zimmerman telegram asking mexico to attack america so the Americans would be occupied. The British Empire intercepted the telegram before it arrived to mexico and showed it to the USA. April 1917 The french solders on the western front were staring to revolt against the government. April 6, 1917 The United States declared war on the Central Powers. Because the USA entering France could stop the revolts. 

During the course of the war the Germans asked Vladimir Lenin to stage an uprising in Russia so the Germans can focus on the western front. March 8 1917 The communist party in Russia revolted. The Bolsheviks won and ended the war with Germany March 3 1918. Even with the soldiers from the east the Germans, Austrians and Hungarians, Bulgarians, and Ottomans were no match for America, France, British Empire, and Italy combined. September 1918 The Bulgarian Empire surrendered to the Allies. The Ottoman Empire couldn't handle the cost of the war and on October 30 1918 The Ottomans signed an armistice with the British. November 3 1918 the Austrian Hungarian surrendered. Finally, On November 11 The Germans signed an armistice with the Entente powers. The War Ended with 37 Million dead.