Sovereignty, Augusto Pinochet, and legal positivism

The imperativist strand of positivism derives law from an actual person or set of persons wielding a monopoly of force. The rule-based positivism of H.L.A. Hart has more sublty identified a matter-of-fact rule of recognition in place of such a sovereign one or many. But sovereignty is not a matter-of-fact of any kind; rather it is partly the product of what I call qua arguments. I reconstruct the reasoning, in the extradition case of Augusto Pinochet in the British House of Lords, providing a focus for an account of the limits of legal positivism in the application of the principle par in parem non habet imperium. Sovereign power is interpreted through reasoning that is at its margin more moral than technically legal.