* Geopolitical Isolationism: The United States had a long tradition of isolationism, which meant that it avoided entangling itself in European affairs. This policy was based on the belief that the US could best protect its interests by staying out of conflicts that did not directly affect it.
* Cultural and Economic Ties: The United States had strong cultural and economic ties to both Britain and Germany, the two main belligerents in World War I. Many Americans were of British or German descent, and there was a significant amount of trade between the US and both countries. This made it difficult for the US to take sides in the conflict.
* Lack of a Clear Threat: At the beginning of World War I, it was not clear who would win the conflict. The US was therefore reluctant to enter the war on one side or the other without knowing what the outcome would be.
* Wilsonian Idealism: President Woodrow Wilson believed in the principle of self-determination, which meant that peoples should be allowed to govern themselves. He was hopeful that the war could be resolved peacefully through diplomacy and that the US could help to create a new world order based on peace and cooperation.
However, as the war progressed, it became increasingly clear that the United States would have to take sides. The sinking of the Lusitania in 1915 and the revelation that Germany was planning to attack the United States in Mexico led to a growing sense of outrage among Americans. In April 1917, the United States declared war on Germany, marking the end of its neutrality.