From the late thirteenth or early fourteenth century, the Swiss Confederacy has evolved from looser to tighter confederation of small sovereign states. The 1848 Federal Constitution establishing a "federation" in Watts's sense was characterized by a combination of two core elements that had different origins. The basic principles of democracy and the rule of law, which were embodied in the constitutions of the liberal cantons. Until 1866, freedom of settlement was, however, restricted to fellows of Christian creed leaving Jews aside; and a federal structure along the lines of the 1787 Constitution of the United States featuring a bicameral system as the cantons' most important vertical channel of influence. Switzerland's political system remains an exception–often denoted as Sonderfall–among modern democracies. The far-reaching autonomy of, and equality between the cantons, their rights to participate in the decision-making processes of the Federation, as well as their duty to cooperate, are at the core of the Swiss federal state.