The U.S had policies after World War 1 to stay out of European warfare. Until the Japanese bombing of Pearl Habor, the U.S joined in the fight to defeat Japan and Germany.
The French had a weak defense and the thick forest they thought would keep the Germans away was a huge flaw to keeping France safe.
Hitler made the Luftwaffe-the German airforce, they bombed London mostly. At the end of August the British made a radar that could detect an invasion from the Geramans. Later Hitler declared that the invasion of Great Britain was indefinitly.
Hitler took these countries to frighten the Soviet Union. He thought if he took the Soviet Union that Britain would fall instanly. Hitler wanted a spring invasion but was stopped by delays in some countries. They had invade early fall which was a huge mistake due to the cold Russian winter.
The army of Japan made an warfare attack on neutral USA territory of Pearl Harbor.
Pearl Harbor was an USA navel base in Hawaii. Killed many USA navy and citizens and this event is what makes the USA join in the the world war.
With the USA coming into the war; the British, Americans, and the Russians put their political differences aside to defeat the Germans.
The war has turned against the Germans.
The USA navy stopped the Japanese from invading Australia.
The Allies wanted Germany, Italy,and Japan surrender completly.
Hitler knew he could not defeat the Soviet Union due to the Soviet Union'war's tatics to keep pushing back the Germans.