After conquering and subjugating the South (most today would call it 'freeing the slaves' and 'reconstruction'), the Fed Govt and its backers (Big Corps) turned West and continued conquering the Indians, and afterwards began looking overseas for conquests.
Actually, the theft of indian land was at its maximum DURING
the civil war. They took most of the Indian land while
the world was watching the silly little war of economics that was going on.
There's only one thing to do to solve the war issue- Make a law making it illegal to wage war. I'm sure the neocons would go for that!