The fifth anniversary of the 9/11 attacks revived familiar lines of debate about the significance of terrorism. On one side are those who believe that 9/11 brought into stark relief a deadly new challenge to our values and existence, an enemy that must be faced resolutely and fought on every front. On the other are those who believe that 9/11 gave birth (or rebirth) not to a new form of threat but to a noxious form of politics: self-righteous, muscular and xenophobic. It is to this stand-off that Robert Goodin makes a refreshing and much-needed contribution. Goodin is a rare commodity: a political philosopher who remains resolutely focused on the problems and controversies that bedevil the real world of politics and policy. His most recent offering, What’s Wrong with Terrorism?, sets out to make a ‘moral assessment of the phenomenon of terrorism and reactions to it’, asking: ‘what is the distinctive wrong of terrorism? … what makes terrorists different from, and morally even worse than, ordinary murderers, kidnappers, and so on?’