Reason to know in the international law of command responsibility

A recent report by the Australian Defence Force arrived at a conclusion that further investigation was not warranted of commanders regarding their responsibility for failing to investigate suspicious behaviour of subordinates in Afghanistan, who were accused of violations of international humanitarian law. This troubling conclusion calls for a better analysis and understanding of command responsibility in international law and gaps in the law of command responsibility. This article identifies the conflicting precedents and scholarship regarding the law of command responsibility, which create uncertainty, and proposes a clarification of that law, with a special focus on the reason to know standard that triggers responsibility for failing to prevent or punish war crimes. It refutes the popular claim that commanders must act wilfully, and it rejects the common dichotomy between a commander who orders or otherwise directly participates in the war crimes of subordinates and one who unwittingly fails to prevent or punish such crimes. Using the empirical psychological literature, the article further explains how commanders can insidiously signal toleration of war crimes without giving direct orders. Finally, the article argues that international law, by absolving commanders who fail to properly train their subordinates to respect the law of armed conflict, misses a rare opportunity to deter war crimes, and offers some suggestions to fill this gap in the law.