Everyone is surprised and dismayed when humans go to war. Everyone thinks there are less violent ways to resolve differences.

Sometimes war is inevitable. Philosophically, ethically, morally,Western culture is reluctant to go to war--until they are directly attacked. In western culture, it's considered cowardly and unethical to target civilians directly. In arab and muslim cultures, anything is fair in war. Examples? The Iraqi repression of Kurdish dissent; Saudi Arabia,Syria,Iran, Morocco, Algeria, Afghanistan, Turkey, Jordan...etc, repression of their native dissidents. Dictatorship is the governance of choice in these societies.
Objectively, one has to say that it's human nature to war. You don't agree? Name me ONE period in history without war! Now, if war is a "normal" part of human societal relationships, what can we do to eliminate it, or at least minimize it's awful effects?

I think that as the world moves toward a universal civilization, a kind of supra-policing methodology will come to be. It will incorporate aspects of traditional policing, military, economic and political tactics.

One of the first aspects of civilization that will be examined-or should be- is religions' role in causing war.
Belief systems are based on faith...and faith is open to interpretation and error. Communal religion-as opposed to individual ethical systems, must be accountable to the world community when it's beliefs translate into unethical activity.