With the failure to codify, state responsibility for rebels went quiet. After the 1930s, there were no more of the great suites of mixed claims commissions. Scholarship on the topic dried up. Nevertheless, we can follow the trajectory of state responsibility for injuries to aliens by rebels as it split in two. On one hand, we have the International Law Commission (ILC)’s half-century odyssey to codify state responsibility, and on the other, the emergence of international investment law. The story of state responsibility for rebels and its legacy for both the modern law of state responsibility and international investment law have a number of implications for international law scholars and practitioners today: for specific legal issues in the law of state responsibility and international investment law, for our understanding of the development of these fields and for the state of the law today when it comes to responsibility for the acts of armed groups across various fields including international human rights and humanitarian law. Finally, it allows us to put together these fragments of state responsibility for rebels and tells us something about the whole, exposing how today international law prioritises the protection of foreign investment against rebels, and non-state armed actors more generally, in the decolonised world.