Abstract

It is a recurring idea in the history of political philosophy that concepts and doctrines of private law are illuminative of public law and political philosophy. Central among these are contract and the trust. In this paper, I consider the prospects of a third: estoppel. The public law context in which estoppel is most commonly invoked is criminal law, and there especially in the service of understanding the defenses of entrapment and what I call officially induced mistake of law. My question is how well it serves this role – how well the structure of the self-disentitlement that provides the rationales for the defences of entrapment and OIML on the non-exculpatory approach to each is articulated on the model of state estoppel, as I call it. I will argue that it fares well, and so that estoppel merits inclusion on the list of concepts and doctrines of private law that are illuminative of public law and political philosophy. In conclusion I will ask what the moral-expressive content of its deployment in that context is, and argue that, while the doctrines of contract and trust work as means to articulate claims about the basis and limit of political authority, the claim that some cases of state self-disentitlement can be modelled on estoppel represents a commitment to some core principles of the rule of law.