Causes
World War II
The Treaty of Versailles lay the war guilt exclusively
on Germany and forced them to pay billions of
dollars for all of the damage caused to the allied
civilians.
Germany was also forced to give up many of it's
colonies after the 1st world war.  Many Germans
were compelled to leave the homes they had made
in various parts of the world.  
The Treaty of Versailles
The Germans only signed because they had no
choice.  But the resentment was one of the reasons
that WW II happened.
Need for Resources
Japan has very few deposits of the resources that
any industrialized nation needs for production.
By the time it was able to act, much of the Pacific
had already been colonized by the european
nations.  
Most of the resources from asia were shipped to fuel
the industries of Europe and the United States.  
Japan was left out of the loop.
After Japan invaded the southern part of French
IndoChina, President Roosevelt froze all Japanese
assets in the U.S.  This was intended to stop the
import of oil to Japan.  When the Netherlands and
UK followed suit Japan had two choices.  It could
either comply with the U.S and leave china, or it
could invade the oil fields of Indochina.
Japan attacked Pearl Harbor in hopes that the U.S
would be down long enough for it to consoladate its
holding in mainland Asia.  This is what brought the
United States into World War 2
Expansionism
Italy entered the war with plans  to expand it's
holdings.  He had designs on an area of southern
France, Corsica, Malta, Tunisia, part of Algeria, an
Atlantic port in Morocco, French Somaliland and
British Egypt and Sudan.
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