War is the most horrific and destructive expression of human potential. Under its fog unimaginable atrocities are common place. The psychological scars impact generations to come. In the age of nuclear weapons international conflict puts the continuity of life on planet earth at stake.
To prevent international conflict a clear understanding of its underlying causes is imperative.
The vast majority of wars are fought to gain control over over territory and resources. In modern times this is no longer considered a legitimate justification. As such, political leaders often resort to deception when initiating a conflict.
The infinite growth paradigm contributes to conflict by accelerating the consumption of scarce resources.
Strong belief combined with a sense of intollerance or disdain for out-group breeds conflict. While sectarianism is typically associated with religion (Protestant vs. Catholic, or Sunni vs. Shiite for example), conflicts over economic or political identity (communism vs. capitalism, or liberals vs. conservatives for example) engage the same psychology (the tribal instinct).
In modern times retaliation is the most commonly used pretense for war. Every human culture has some concept of the right to self defense. Those who do not retaliate when attacked invite further aggression. The retaliation instinct can be triggered artificially.