Abstract: War used to be a lucrative business. It was waged as a matter of course to expand territory, convert the religion of populations, resolve disputes, collect an unpaid debt, restore property, or punish another sovereign for a treaty violation. This was not only true as a matter of practical statecraft. It was also the accepted ethical prescription of Just War Theory. The modern jus ad bellum has transformed our view of war: From an instrument of self-interest, enforcement and punishment war has been proclaimed an evil which must be carried out only as a last resort and in self-defense. Yet, in this undoubtedly progressive move, we have also lost something – our ability to articulate the precise goals of the war, and consequently, to determine when the war must end. When self-defense is the only legitimate justification for waging war, every goal must be articulated in terms of self-defense and self-defense, in turn, becomes articulated through an endless array of goals: installing a democratic government in enemy territory, improving child literacy, empowering girls and women through education, enhancing agricultural production, building infrastructure or eliminating all terrorist threats around the globe. While the question of whether a military campaign is justified as a matter of self-defense is often debated, the question of what goals actually promote self-defense remains largely unaddressed. The problem lies not so much in lack of attention; rather, it is that even where a just cause of self-defense exists, the law is inadequate in giving us sufficient guidance on what and how much counts as a legitimate security interest. As a result, we can have no consensual vision of what victory can or should look like. Nor do we have a clear metric by which we can argue about it. In a world of perpetual threats, our existing legal framework invites perpetual war.