With one hundred million people in the country, we might think it would not make any difference if we let someone else do our part. But this was not the spirit of America. For the most part, each person himself felt that this was his war, fought for his rights and for his aims. And because for the most part each person acted as if success depended on him, Europe was amazed at America's swiftness in getting ready to fight.
America by tradition aloof
The United States did not decide to enter this war until it had been going on nearly three years, for its people had come from nations fighting on opposite sides. Besides, war had always been a common happening in Europe, and the United States had always tried to keep its hands free. Washington and Jefferson and later Monroe had advised that we should only be "interested spectators" of quarrels abroad.
The powers involved
233. A World at Arms. The outbreak of the war surprised the world by its suddenness. The heir to the throne of Austria, Archduke Ferdinand, was murdered in June, 1914. Austria blamed Serbia for the murder. When Serbia would not agree to all that was demanded of her, Austria at once declared war. The largest nations of Europe were united in two groups. Germany took up Austria's quarrel; Russia, France, and England combined to oppose Germany. Italy was bound to defend Germany and Austria if they should be attacked, but now believed they were the attacking nations, and later came in against them. Bulgaria and Turkey threw in their lot with Germany and Austria, these four nations forming the Central Powers, and Japan and Roumania with the Allies, as the nations opposing them were called.
Invasion of Belgium
Germany's first act was to rush her troops across the borders of Belgium, straight toward Paris. Belgium, of course, was too small a state to stand against the armies of her stronger neighbors. On this account the great nations of western Europe had agreed never to invade Belgium, and now England felt bound to go to her defense.
Events at sea
British, French, and Belgian soldiers, fighting in whatever order they could, checked the on-coming masses of Germans. The Allies stopped them at the Battle of the Marne, far within France. On the sea England's mighty navy quickly put an end to all German shipping. She kept the German navy from venturing even into the North Sea. But German submarines could not be so easily blocked up, and slipped out and sunk Allied vessels.