Warfare is moving towards full weapon autonomy. Already, there are weapons in service that replace a human at the point of engagement. The remote pilot must adhere to the law and consider the moral and ethical implications of using lethal force. Future fully autonomous weapons will be able to search for, identify and engage targets without human intervention, raising the question of who is responsible for the moral and ethical considerations of using such weapons. In the chaos of war, people are fallible, but they can apply judgement and discretion and identify subtle signals. For example, humans can identify when an enemy wants to surrender, are burying their dead, or are assisting non-combatants. An autonomous weapon may not be so discerning and may not be capable of being programmed to apply discretion, compassion, or mercy, nor can it adapt commanders’ intent or apply initiative. Before fully autonomous weapons use lethal force, it is argued that there needs to be assurances that the ethical implications are understood and that control mechanisms are in place to ensure that oversight of the system is able to prevent incidents that could amount to breaches of the laws of armed conflict.