United States declaring independence in 1776 marks an important turning point to nationhood besides the beginning and the end of this war.
During this Declaration that happened on July 4, 1776, 13 American colonies cut their political ties with Great Britain.
Answer:
This is what i found "On September 27, 1940, the Axis powers are formed as Germany, Italy and Japan become allies with the signing of the Tripartite Pact in Berlin. The Pact provided for mutual assistance should any of the signatories suffer attack by any nation not already involved in the war. This formalizing of the alliance was aimed directly at “neutral” America—designed to force the United States to think twice before venturing in on the side of the Allies."
The intercepted Zimmerman note and the Germans sinking the American ship, Lusitania