There will always be war. There will always be people who want power, or whatever it is that other people have, and will be willing to kill to get it.
The best we are ever going to be able to do is carve out areas of the world where Renaissance and Enlightenment principles reign, and where people are willing to fight to preserve them against those who don't share them.
Unfortunately, those things -- the principles, and the willingness to defend them -- are being rotted from within at increasing speed. Could be that it's an inevitable cycle of human nature. I had only hoped I wouldn't live to see it.