depends on who us is
yes it was vital 4 the US 2 enter World War 2 because we needed their help 2 win the war. It turns out tht because of them we won the war.
World War 2
Germany declared war on the US. The US entered World War 2 because of the Pearl Harbor raid.
08 Dec 1941
1909 to 1944 The US entered World War 2 in December of 1941.
on decmber 8 1941