April 6th, 1917
Yes
April 6
The United States of America joined the Allied Nations in World War II.
France and Great Britain
It was bad idea for America to join World War 1 because of the impending war spending that would severely damage the economy. Also, the loss of men to war casualties would lead to labor unrest.
America joined because of Pearl Harbor.
2 years
America did not join the League of Nations
Yes
dec 8 1942
Britain declared war on Germany on 3 September 1939 and America declared war on Japan on 8 December 1941
They were enemies, they started fighting after Pearl harbor.