The Philosophy of Force presents a highly original, republican theory of just war. Taking its inspiration from historic wars against slavery and colonialism, it offers an account of the ethics of defensive violence shaped around the perspective of those oppressed by empire and other forms of social and political domination. Whereas the most intuitive cases of just war are often thought to be those fought against mass killing, more can be learnt about the ethics of violence by focusing on wars against mass domination-wars like the slave revolt in Saint-Domingue that gave birth to Haiti and the American Civil War's emancipation of enslaved people.

By contrast with liberal-cosmopolitan ethics, this book argues that the right analytical starting point for thinking about war and political violence is the use of lethal force to defend against enslavement, not the defence of lives against attempted murder. Enslavement highlights the importance of dominating power as a facet of all violent threats and illuminates more fully than other types of threat the intimate relationships between violence, vulnerability, and social domination. Building a republican account of war ethics around this insight helps identify distinctively political dimensions of violence that are otherwise apt to be overlooked. It provides a compelling basis for understanding the legitimacy of armed defence against a wide range of threats, some lethal, some not.