Abstract
The present paper consists of two closely related parts: one which outlines a normative criterion for evaluating the legitimacy of constitutional change and one which specifies a particular proposal of a constitution. The criterion used stems directly from the "pragmatic" brand of contractarianism developed by Buchanan, where an approximate rule of unanimity is utilized. The proposal aims at the highest possible freedom of choice for individuals when it comes to defining the political system of their liking: a core (dealing with public goods and rights) is common for all, but everything else can vary between different sub-constitutions between which individuals choose.