World War I, also known as The Great War, was from 1914-1918. This mainly European war was triggered by the assassination of Franz Ferdinand, the heir to the Austria-Hungary throne. Two groups were formed, the Central Powers consisting of Germany, Turkey, Austria and the Allied Powers with France, Great Britain, and Russia. The United States was reluctant in entering the war but ultimately numerous events led the US to declare war on Germany in 1917. The German Naval Policy, American economic links and interests, and most importantly Woodrow Wilson's idealism all to a certain extent influenced the United States to intervene in the First World War.
In 1914, the Germans stated that the seas around Britain were a war zone and were blockaded. They warned that if they sight ships attempting to enter the war zone they would be risking the chance on being sunk by German submarines. The Germans used unrestricted submarine warfare and sank several ships. When the Americans found this out, they felt that this was a violation of neutrality rights and therefore an act of war. The Americans were neutral so deserved to send ships through the war zone. When the Luistania was sunk in May 1915, killing 128 Americans, it caused an increase in anti-central sentiment. Another attack on the Arabic was made as well. This led to the agreement on the Sussex Pledge, which stated that Germany would not attack without warning. Germany broke this pledge and continued with the unrestricted submarine warfare. President Wilson broke off relations with Germany and caused the American to join WWI.
The Americans had been loaning $3billion to Great Britain and France and needed to make sure that the loan would be paid off or else the US economy would suffer immensely. The Americans realized that if the Central Powers won the war they would not be getting this money back. During the war, trade increased with European nations and helped the US economy prosper.
