Three schools of thought that were prevalent in the United States regarding our involvement in World War One included Neutrality, the Preparedness Movement, and Moralism, which I will now break down for you starting with Neutrality that was exemplified by President Woodrow Wilson attempting for the first 2 and 1/2 years of the war to keep the United States out of the conflict. Wilson also kept the American economy on a peacetime basis and made no preparations for war. Other supporters of American neutrality involving World War One were the Pacifists, led by William Jennings Bryant, Henry Ford, Senator Robert M. LaFollette, Senior, and the Woman's Leader Jane Addams, who wanted to keep America out of the war at all costs, the Liberal Internationalists led by President Woodrow Wilson and President William Howard Taft, the Atlanticists who were led by President Theodore Roosevelt, Senator Henry Cabot Lodge, and Senator Eliku Root, business leaders, such as Henry Ford, who wanted to sell arms and war-related supplies to all participating countries in the war including England and Germany, as well as loan them money and extend them credit, the Working Class that was divided along ethnic lines, the Black Community that did not take a particularly strong stand either way until America was drawn into the war, and the Political Parties who remained mostly out of the limelight as demonstrated by President Woodrow Wilson campaigning on his famous "He Kept Us Out of War" slogan, and the Socialist Party that supported peace.
The unprovoked attack and sinking of the Ocean Liner RMS Lusitania on May 7, 1915, that was sunk by the German U-Boat U-20 off the Old Head of Kimsole, Ireland and killed 1,198 passengers including American citizens, had a very strong effect on public opinion that felt the United States needed to immediately build a strong Army and Navy for defense of the country. This school of thought, known as the Preparedness Movement, was led by President Theodore Roosevelt, Elihu Root, Henry Stimson, and General Leonard Wood. The Preparedness Movement supported that every American male, upon their 18th birthday, should undergo 6 months of military training and be assigned to military Reserve Units, going as far as to establish their own training camps in places like Plattsburgh, New York. The Preparedness Movement also wanted abandonment of the National Guard and large Federal Reserves.
The third school of thought for America about entering World War One was Moralism that felt that going to war was necessary and wise as America was the only great nation devoted to democracy and freedom. This movement was led by William Jennings Bryant, Jane Addams, and President Woodrow Wilson who wanted World War One to be the war to make the world safe for democracy. Moralism was also fueled by German atrocities in places like Belgium, Germany's violations of International laws, Germany dropping bombs from Zeppelins on innocent civilians, Germany using poisonous gas on civilians, Germany sinking several passenger ships with their submarines, and the wide held belief that Germany was a threat to America.