Question

Why did the U.S. delay entry to World War I until 1917?

Answer 1

In early 1917 Berlin forced the issue. Its declared decision on 31 January 1917 to target neutral shipping in a designated war-zone became the immediate cause of the entry of the United States into the war

Answer 2

If your answers were the same as mine, You'd be looking for " The U.S. had previously held a policy of isolationism"