Japan has been at war already, but after they attack on Pearl Harbor, the US declared war on them the next day 1942
On Japan.
Any country can declare war on anybody else. What matters is can you back it up?
the us didn't declare war on china in world war 2 us declared war on japan on 1941 when japan bombed pearl harbor hawii
1945
Japan attaking pearl harbor
no, japan did not formally declare war Germany declared war on u.s. after u.s. declared war on japan
The Mukden Incident ~ see related link below .
Sorry for that last answer. Some people. It all started with Pearl Harbor for America. Since so much damage was inflicted, Roosevelt soon asked the UN to declare war on Japan.
The United States was bombed by the Japanese at Pearl Harbor which cause a declaration of war but Germany had an alliance with Japan and it had forced the United States to declare war on Germany too. Then Germany had an alliance with Italy which cause the United States to declare war on yet another country. Then the world was at war and therefore World War 2 started.
This statement is true. Japan started the war with the United States when they attacked without warning and did not declare war on the US. Within days Germany declared war on the US and the US declared war on Japan. The US then entered World War 2 as well as Japan.
December 8, 1941, the day after the Japanese attacked Pearl Harbor
The immediate cause was Japan's attack on Pearl Harbor. This caused the US to declare war on Japan, which led to Germany and Italy declaring war on the US.