The correct answer to this open question is the following.
Most Americans sympathetic to Britain and the Allied Powers during the early years of World War 1 because the US government had maintained a foreign policy of neutrality and did not want the US to enter the war. So American people, looking from afar, supported this decision of the government and the fact that many American companies supplied weaponry, raw materials, and all kind of supplies to the Western European nations.
However, the sinking of the Lusitania ship and the interception of the Zimmerman's telegraph in which Germany asked México for help in the war, made the US change its foreign policy and the United States entered World War 1 on April 6, 1917.
