Operating under responsible command is an essential requirement to qualify as a lawful combatant, and is also central to the doctrine of command responsibility. This reveals the inextricable link between the role of the commander and the effective implementation of the international humanitarian law (IHL). Understanding this linkage is vital to ensuring that commanders and other military leaders fulfil their obligation to prepare subordinates to navigate the chaos of mortal combat within the legal and by implication moral framework that IHL provides. Few commanders would question the proposition that responsible commanders prepare their military units to effectively perform their combat missions. However, operational effectiveness is only one aspect of developing a "responsible" command. Because this term is grounded in the expectation of IHL compliance, a truly responsible command exists only when the unit is prepared to execute its operational mission in a manner that fully complies with IHL obligations. This broader conception of a disciplined and effective military unit reflects the true nature of the concept of responsible command, as only military units built on this conception of discipline advance the complementary objectives of military effectiveness and humanitarian respect. Accordingly, the requirement that lawful combatants operate under responsible command is an admonition to all military leaders that truly effective military units are those capable of executing their missions with maximum operational effect within the framework of humanitarian constraint that defines the limits of justifiable violence during armed conflict.