It is increasingly common to claim that terrorism is different from other bad things, such as crime, because it is essential to prevent terrorism, rather than simply to hunt down and punish its perpetrators. For example, Jacqui Smith, the Home Secretary, maintains that ‘In many respects, counter-terrorism work is distinctive in nature and not like other areas of law enforcement. The work of our security and intelligence agencies is, of necessity, covert…..We depend on the police and Security Service to identify these individuals before their plans come to fruition, to stop an attack from happening. This contrasts with the majority of police investigations, which happen after the crime has taken place'. I think we should treat such claims about the exceptionalism of terrorism with care, not because terrorism isn't sui-generis in important ways, but because the ways in which it is exceptional are likely to depend on how one understands other bad things, such as war, crime or illness. Hence, the exceptional features of terrorism are likely to prove matters of degree, rather than kind. For all great evils, including crime, prevention is preferable to redress. We should therefore prioritise the prevention of murder, rape, corruption, fraud, the spread of Aids or cancer over post-hoc efforts at redress, important though these are, because such things ruin people's lives and destroy societies, whether or not they are also meant to terrorise.