Why didn't the US enter WWI when it started?

When World War I started, the United States did not enter the war. There were reasons for this. Americans were strongly divided about our involvement in World War I. There were many people of British descent who supported Great Britain. However, there also were many people of German descent that supported Germany. Additionally, many people also believed that the events that led to the start of World War I had nothing to do with the United States. President Wilson believed it was in our best interest to stay out of the war at this time.
The Progressive Era was still a very strong movement in the United States in 1914. There still were things that this movement was working to accomplish. Getting involved in World War I would likely have brought the Progressive Movement to an end.
Eventually, events in World War I drew the United States into the conflict. When the Germans began to sink our ships without warning, we eventually joined World War I in 1917.
http://www.digitalhistory.uh.edu/disp_textbook.cfm?smtID=2&psid=3476

https://www.ducksters.com/history/world_war_i/united_states_in_ww1.php

https://www.history.com/this-day-in-history/america-enters-world-war-i