Americans as a whole were and always have been isolationists. It probably stemmed from George Washington's farewell address, and even formed before then. Almost all wars America had been in before the Great War were all fought by themselves. Once the first World War was over they were quick to pull out of the affairs of Europe. Can you blame them? Even if it was the tail end of the war, Americans were still subjected to the past four years of every horror World War One had to offer.