The concept of ‘evil’ has a long history in the western tradition, extending from early theological debate, through tortured discussion of the relationship between moral and religious issues, to a contemporary context in which moral and political theory have domains of discourse in their own right. The religious roots of the idea of ‘evil’, however, have often made it difficult to accommodate in predominantly secular cultures, especially in multicultural contexts where deeply held beliefs may not be widely shared. Indeed, there has been a tendency in recent decades, especially among political theorists, to set the notion aside as outdated or inappropriate. Yet, at an intuitive level, the idea that some things are especially wrong, beyond toleration, still has significant currency. ‘Evil’ is undoubtedly a complex and controversial notion, but it continues to capture something that resonates across cultures in the modern world. We can grant that ‘evil’ is a dangerous and loaded term, readily open to abuse. The simple fact that it remains in currency in so many areas of discourse demands philosophical attention. While there is a small (but growing) philosophical literature on evil, political theory has not revisited the idea systematically.

It is clear that ‘evil’ as a concept is taken seriously in ordinary political debate. Politicians and the press recognise the power of describing something as evil. This is clear in accounts of ‘evil regimes’, an ‘axis of evil’, of evil people such as Josef Fritzl and other abusers of children.