Jus Ad Bellum is a principle in just war theory that determines the conditions under which a state may justifiably go to war. It focuses on the reasons for engaging in conflict, emphasizing that war should only be initiated for just causes, such as self-defense or protecting human rights. This principle also outlines criteria that must be met, including legitimate authority, proportionality, and a reasonable chance of success. By establishing these guidelines, Jus Ad Bellum aims to prevent unnecessary wars and promote ethical decision-making in international relations.