This paper considers whether an act of aggression can subsequently become a justified occupation. I use John Lango's theory of the temporalization of just war principles to argue that the jus ad bellum criteria should be reapplied over time, such that they can be newly met over the course of an intervention. Discussing each traditional principle of jus ad bellum, I outline inherent challenges in ... [Show full abstract] remaking an unjust war as a valid humanitarian intervention. In particular, I argue that right authority is a complex and difficult hurdle for a former aggressor's occupation. The US occupation of Iraq is used as an example of an intervention that initially violated most or all just war principles but came to satisfy them during later phases of the occupation. This paper contributes not only to the question of how to apply just war principles over time but also to the underdeveloped ethics of occupation and jus post bellum.