In this paper, I discuss a distinctively non-paradigmatic instance of punishment: the punishment of non-citizens. I shall argue that the punishment of non-citizens presents considerable difficulties for one currently popular account of criminal punishment: Antony Duff’s communicative expressive theory of punishment. Duff presents his theory explicitly as an account of the punishment of citizens - and as I shall argue, this is not merely an incidental feature of his account.
However, it is plausible that a general account of the criminal law of the kind of idealized state that Duff focusses on will need to say something about how that law deals with non-citizens. In particular, I claim, it will need to provide a justification for punishing them. Because Duff's account says nothing about the punishment of non-citizens, it cannot do so. Furthermore, although Duff's more recent suggestion that non-citizens should be thought of as being guests in the state on whose territory they are present may provide for an account of their criminalization, it cannot easily be extended into an account that provides a justification for their punishment.