War can be avoided if the people in power choose to avoid it at all costs and take the right steps to avoid it.
For example:
During the height of the Cuban Missle Crisis, JFK received two letters from the Russians. One was very bellicose and seemed to be almost promising war whilst the other was very clearly anti-war. One was clearly a fake, but which one? Everyone was completely at a loss for what to do until Robert Kennedy said, "Just respond to the anti-war one" which is what happened. It turned out this was indeed the real letter and thankfully, in part, this is what helped us avoid war.
Take care all.
