In a nutshell this war was started by a whole bunch of people who just went crazy at the same time. You can probably think of World WarII as a whole bunch of different conflicts that kind of merged into one gigantic war. I have had the opportunity to meet several WWII Military ring customers in my day, but if there are many more of you out there please speak up. Most of my military ring customers come from a later era. 

WWII was known as a global military conflict where most of the nations of the world ended up being aligned in one of 2 opposing alliances, the Axis powers and the Allies. There were over 100 million personnel mobilized for the war, and at the end there were over 70 million KIA's which were mostly civilian. This war was the epitome of a total was because the economies and resources of many countries were tied up in it.

I'm sure that all of my custom military ring customers are aware of Hitlers invasion of Poland in his quest for world dominance. This brought most of the other European countries into the war. They knew that they had to band together in order to not be conquered.

Japan and China had their own thing going on because Japan was also seeking world domination. Their attack on Pearl Harbor finally brought the US into the war. Thats not all folks. Italy was attempting to subjugate Ethiopia under Mussolini also. Since everybody was fighting anyway each country just got in where they fit in. I don't know what was in the coffee that day but it was definitely stronger than 151 rum.