At the beginning of the 20th century the United States was the most powerful country in the world. The world leader in coal and steel production, the USA was also a major producer of raw materials. The most important of these being wheat, cotton and oil, which accounted for more than a third of all the USA's exports. With a population of over 100,000,000, the USA had the potential to decide the outcome of the First World War. However, in 1914, the country had no overseas alliances and on 19th August, President Woodrow Wilson declared a policy of strict neutrality.

Although the USA had strong ties with Britain, Wilson was concerned about the large number of people in the country who had been born in Germany and Austria. Other influential political leaders argued strongly in favour of the USA maintaining its isolationist policy. This included the pacifist pressure group, the American Union Against Militarism.

Some people in the USA argued that the country should expand the size of its armed forces in case of war. General Leonard Wood, the former US Army Chief of Staff, formed the National Security League in December, 1914. Wood and his organisation called for universal military training and the introduction of conscription as a means of increasing the size of the US Army.