Abstract
Since the twelfth century, political orders in Europe have been built around the notion of the rule of law, which has been articulated differently at different times and in different legal systems. Beyond these particularities, comparative legal history and comparative law enable us to identify a shared legal culture. In the Middle Ages, the legal tradition of the universities served to create an instrument of " police et justice " tending towards the ideal of " bon gouvernement ". Throughout the ages, law has maintained this irreducible role, ensuring that every political decision is measured against a yardstick of justice. Whatever European construction is envisaged, the question of the rule of law at the service of an effective and just policy is essential. The ideal of European law and its history reflect this constantly renewed recomposition.
