I think that may be realistic. The more backstabbing, the more need for a 'pre-emptive defense' of wiping someone else out before they get you. Certainly military buildups happen in real life where there is military aggression. Warmongers might not care about more wars. Friends who support each other against aggression would get the helping-us-with-the-war bonus and hence would reinforce their good relations. Even less likelihood of war there. Also, don't forget the puppet masters who manipulate war and peace. They might have a more difficult task, but I'm sure they are up to the challenge!