By 1918 all of the Great Powers of Europe were exhausted by four years of war. However, a fresh power outside of Europe had recently committed itself to join the fight as well: the United States. Provoked by German unrestricted submarine warfare and the discovery of a German plot to induce a Mexican attack on the United States, President Woodrow Wilson asked congress to declare war on Germany in April 1917. It would take some time, though, for the United States to mobilize and deploy significant forces to Europe.
In March of 1918 the Germans, drawing upon troops freed up from the eastern front following the Russian revolution, would attempt to break the French and British before the Americans could arrive. This attack, the Kaiserschlacht or Emperor’s Battle, was made up of four separate offensive. Three were to serve as diversions, while the fourth offensive, code-named Michael, was to drive through the British at the Somme and make for the sea to cut them off.
Early on Michael saw stunning success, advancing at a rate not seen since the beginning of the war. The Germans came to within seventy-five miles of Paris, close enough to begin shelling the city with their sixteen inch guns. The advance had been too rapid, though, as the Germans outran their supply lines. As Michael was running out of steam American troops began to arrive on the battlefield, tipping the balance and halting the Kaiserschlacht for good.
By August, with nearly two million fresh American troops had arrived on the continent, the Allies would counterattack against the Germans. This so-called Hundred Days Offensive hurled the Germans back, undoing all of their gains from the spring and pressing towards Germany. Recognizing that Germany could no longer win the war, Hindenburg and Ludendorf told the Kaiser to maneuver for a favorable peace. When the Kaiser called for the German Navy to take to sea to strike a blow to the British that might improve their bargaining position the sailor mutinied. The mutiny expanded, and turned to a revolution that would sweep the German Kaiser from power and replace him with a new government that sued for peace. The war was over.