Constitutional Reason of State

24 Pages Posted: 18 Aug 2015

See all articles by Thomas M. Poole

Thomas M. Poole

London School of Economics - Law Department

Date Written: July 27, 2015


This paper defends reason of state as an explanatory category. It begins with an analysis of the law relating to the prerogative, before observing that prerogative cases are much less typical today than an expanding suite of cases involving related matters but where the power in question is sourced in statute or the constitution. The long-term historical narrative towards the constitutionalization of reserve powers can thus be expressed as a move from a princely model of reason of state, epitomized by prerogative, to a polity or law-based model of reason of state, whose characteristic form is statute. Locke’s analysis of prerogative is seen as a classic early-modern account of the princely model. Hobbes’s state theory provides the basic script of the polity model, but it is in the republican theorists of the same period, notably Harrington, that we see a recognizably modern concern to normalize reason of state through constitutional and institutional design. The paper then takes issue with modern liberals who follow Hayek in wanting to remove the concept of reason of state from constitutional politics altogether. Such an approach can only work if the state is itself made to vanish, or if a liberal state disengages from interaction with other states. Neither option is plausible. The paper ends with a reflection on the value of the category of reason of state for constitutional theory.

Suggested Citation

Poole, Thomas M., Constitutional Reason of State (July 27, 2015). LSE Legal Studies Working Paper No. 16/2015, Available at SSRN: or

Thomas M. Poole (Contact Author)

London School of Economics - Law Department ( email )

Houghton Street
London WC2A 2AE, WC2A 2AE
United Kingdom


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