Jus post bellum (/juːs/ YOOS; Latin for "Justice after war") is a concept that deals with the morality of the termination phase of war, including the responsibility to rebuild. The idea has some historical pedigree as a concept in just war theory.^[1] In modern times, it has been developed by a number of just war theorists and international lawyers.^[2] However, the concept means different things to the contributors in each field. For lawyers, the concept is much less clearly defined, and many have rejected the usefulness of the concept altogether.^[3] The concept continues to attract scholarly interest in the field of international humanitarian law.^[4]

Background

Brian Orend cites Immanuel Kant as the first to consider a three-pronged approach to the morality of armed conflict^[5] and concluded that a third branch of just war theory, the morality of the termination phase of war, had been overlooked.^[6] A related concept to the jus post bellum is the lex pacificatoria, the law of peacemaking by treaty^[7] to introduce the jus post bellum phase.^[8]

Purpose

The purpose of the concept and its usefulness depends on whether it is considered as a moral or a legal concept. Its usefulness as a matter of law is very unclear. As a concept in just war theory, the jus post bellum debate considers a number of issues:^[9]

• Provide terms for the end of war; once the rights of a political community have been vindicated, further continuation of war becomes an act of aggression.
• Provide guidelines for the construction of peace treaties.
• Provide guidelines for the political reconstruction of defeated states.
• Prevent draconian and vengeful peace terms; the rights a just state fights for in a war provide the constraints on what can be demanded from the defeated belligerent.

Thus, the areas within which jus post bellum applies can include restraining conquest; political reconstruction, especially in the case of genocide and war crimes; and economic reconstruction, including restoration and reparations.^[10]