You know, off the top of my head, with the possible exception of WW1, I can't think of any war that wasn't started over money, land, or resources.
WW1 was really pretty senseless in the way it was allowed to begin. Europeon alliances just got outta hand, and one mistake lead into another.
7mm
I really believe that the U.S. getting involved in WW 1 brought the whole world to disaster. There was a 20 year truce and rearming and then hell on earth for Europe and Asia which ended up under murderous communist dictatorships. If we had never fought Spain and steered clear of the European war it probably would have ended in basically a stalemate around 1920. It's extremely hard to imagine it could have turned out worse.
