Steven Pinker

The logic of the Leviathan can be summed up in a triangle. In every act of violence, there are three interested parties: the aggressor, the victim, and a bystander. Each has a motive for violence: the aggressor to prey upon the victim, the victim to retaliate, the bystander to minimize collateral damage from their fight. Violence between the combatants may be called war; violence by the bystander against the combatants may be called law. The Leviathan theory, in a nutshell, is that law is better than war.

Steven Pinker, The Better Angels of Our Nature: Why Violence Has Declined, New York, 2011, p. 35