Ethical approaches to war require that we don't value only the lives of 'our' people, as Realism asserts; that we don't enforce our sense of justice with weapons, as Militarism demands our 'moral warriors' do; that force is used only in self-defence, based on the principles of Just War Theory. However, can there be purely defensive or moral wars? This book offers unique insights into twenty-first century warfare through three approaches – Realism, Militarism, and Just war Theory – in the context of 'precision' weapons, celebrated for minimising risks to soldiers and civilians. The author questions whether the rapidly developing technology of lethal autonomous weapons is actually expanding an existing legal-ethical issue: the problem of civilian harm. Laws permits acts that cause incidental civilian harm; AI warfare puts the law's accountability gap into sharper relief, highlighting the need for new accountability mechanisms that reflect a sense of legal and moral justice.