Historically, a predecessor state’s responsibility for wrongful acts did not transfer to a successor state. Nevertheless, over time, this view has evolved to include the acceptance of responsibility in certain cases – creating ambiguity in the state of the law. To address this ambiguity, the United Nations (UN) International Law Commission (ILC) added ‘Succession of States in respect of State responsibility’ to its program of work with the objective of identifying and codifying existing and emerging rules – culminating in the creation of the Draft Articles on Succession of States in Respect to State Responsibility. But what effect will this work have in practice for investor-state disputes? In addressing this question, this article concludes that the ILC’s work has codified crucial elements in the laws of both state succession and state responsibility, and therefore should be consulted when practitioners are developing their case strategies.