Over the past quarter century democratic governments have generally sought to subordinate discretionary policy to a framework of rules. This is the way monetary policy now works. Interest rates are no longer set by politicians. There is a stated inflation target, and an independent body is charged with meeting it. Likewise,the international system of trade and payments operates increasingly on similar principles. The World Trade Organisation is widely seen by anti-globalisers as a means of entrenching the privileges of the rich world. The opposite is true: a system of rules applying to all member states means that economically stronger countries cannot discriminate against foreign producers and in favour of their own vested interests. It is a way of subordinating potential conflict to the rule of law.

A rules-based system ought, over the long run, to be a more efficient form of governance, as well as a freer one, because it makes policy more predictable and allows private citizens to get on with their lives without an overbearing government. The principal lacuna in the creation of a rules-based system is, however, that in relations between states there is no ultimate sovereign authority that can implement the decisions of the international community. It is possible that Mr Blair has this in mind when he elevates the national interest to a principle higher than the rule of law. It is certainly the justification of his belief in humanitarian intervention against oppressive states.

But that reservation has no place in the practice of domestic government. The rule of law must run because it serves our interests best over the long run, even if in particular cases — say the workers of BAE — there are individual losers. A society in which the rule of law may be dispensed with if it runs counter to government objectives is a terrible precedent. Worse governments than Mr Blair’s will turn to it.