Abstract

Criminalisation theorists who try to explain when substantive criminal law may appropriately be deployed to shrink the scope of our presumptive initial liberty, often take their project as requiring them to identify the sorts of conduct for which may the state criminally convict. I argue that this is a mistake. While such theories of ‘convictability’ have their place, they do not completely explain the use of substantive criminal law to limit our presumptive initial liberty. Convictions ensue only after pleas of justification and excuse fail, but the substantive criminal law coercively limits liberty well before conviction, when it creates a pro tanto criminal proscription. Even those who can escape conviction by pleading a justificatory or excusatory defence were, in fact, subject to authoritative criminal law guidance proscribing (or sometimes, requiring) specified conduct. Although that guidance is sometimes trumped by the additional guidance contained in defences, it is not null and void, and it continues to have a liberty-limiting effect. In other words, substantive criminal law already shrinks our initial liberty by pro tanto criminally proscribing some conduct. Therefore, I argue that we also need a theory of criminalisation that addresses the appropriate domain of pro tanto criminal proscriptions.