Guns have little to do with it. Before guns it was swords... before swords it was clubs... before clubs it was rocks. It's purely man's greed, lust, and intolerance. Everything else is just tools... money being one of the most effective tools of warfare/oppression. Here is an interesting bit...
http://www.kamron.com/economics/people_ ... he_frb.htm
I am convinced that interest-ed, debted money is the reason for most wars today.
http://www.financialsense.com/contribut ... the-dollar
Just one of many articles on the subject. Next time we are about to wage war, think about it in the sense of money... not "terrorists."