The manner and context in which a federal system comes into being has a distinct and pervasive influence on the kinds of governing institutions and decision-making processes that are adopted within that system. Every federal constitution establishes a particular set of representative institutions, configurations of power and amending processes. A close analysis of the formative basis of a federal constitution – understood as a complex set of political mores, institutions and laws – sheds significant light on the terms and structure of that constitution. Thus, the various kinds of federal system can be classified by reference to their peculiar formative processes, as well as by reference to the influence of those processes on the representative structures, configuration of powers and amending processes adopted under the federal pact – and not by reference only to those outcomes in abstraction from the processes that led to them. As will be seen, the lines of influence generally move from formative basis to representative institutions and configurations of power, and then, in turn, to the amendment processes adopted thereunder.