Jus post bellum

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. In modern times, it has been developed by a number of just war theorists and international lawyers. 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. The concept continues to attract scholarly interest in the field of international humanitarian law. A famous example of Jus post bellum is the reconstruction of Germany by the Allies post World War 2.

Brian Orend cites Immanuel Kant as the first to consider a three-pronged approach to the morality of armed conflict and concluded that a third branch of just war theory, the morality of the termination phase of war, had been overlooked. Part of this morality, according to Michael Walzer, is that we have a moral obligation to not leave the regimes intact that caused the war in the first place. However, the actual duty of the role of jus post bellum remains unclear. To achieve a lasting peace, the goal is to find a balance between transitional justice and order. A related concept to the jus post bellum is the lex pacificatoria, the law of peacemaking by treaty to introduce the jus post bellum phase.

The purpose of the concept and its usefulness depends on whether it is considered as a moral or a legal concept. As a concept in just war theory, the jus post bellum debate considers a number of issues:

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.

When a state does help reconstruct another state after winning a war, they (as well as other international actors) have their own incentives to create new power structures that favor their state. Additionally, if the population doesn't accept the reconstruction or otherwise feel their grievances have been met, the very act of reconstruction can be seen as violence, and further conflict, just appearing in a different form.

James Pattison argues that the belligerent shouldn't have a responsibility to rebuild to justify the morality of a war. Jus post bellum should only play a role in determining post war justice. There are many problems with the assumption that only the belligerent should rebuild: