Prior fault: blocking defences or constructing crimes

When assessing a defendant’s (D’s) liability, the orthodox approach of the criminal law is necessarily narrow and precise in its focus. We do not ask, for example, whether D satisfies an offence mens rea ‘at some non-specific point in D’s life’, or whether ‘all things considered’ we believe she is deserving of a defence: such questioning may help us assess D’s moral character, but they are too general and too subjective to drive the enquiries of criminal law. However, without some flexibility, this approach is vulnerable to creating unwanted results, most obviously in relation to criminal defences. For example, D decides to kill her enemy V. D taunts V in order to elicit a violent reaction. V attacks D (as D anticipated) and D kills V in ‘self-defence’. In this case D has created the conditions of her own defence in order to commit a serious wrong, and thus her defence must be blocked. This ‘blocking’ is achieved through the doctrine of prior fault. The doctrine of prior fault has attracted considerable academic comment, with much of this criticising perceived inconsistencies within the doctrine. In this chapter, the aim is to discuss and evaluate both the doctrine of prior fault itself and those claims of inconsistency. The chapter begins by rationalising the areas of law where issues of prior fault arise, distinguishing its application to defences (where it can act to block a defence) from its application to rules of offence construction (where it becomes an inculpatory rule). By recognising and highlighting the different contexts within which the doctrine of prior fault operates, the chapter is able to justify certain inconsistencies (between categories) whilst exposing other problematic issues and inconsistencies (within categories).