Origins

The idea of the separation of powers has been subjected to criticism and competition ever since it first came to be during the upheaval of the English Civil War in the 1640s. Since then, it has been dismissed as often as its virtues have been extolled. In recent years the case has once again been stated that the idea of the separation of powers has lost its significance in a globalised world, with a power constellation in which the distinctions between different types of ‘powers’ have blurred and even so-called constituted power holders have become more and more diffuse. Yet even its fiercest opponents cannot deny that the idea of the separation of powers as a theory of government has, in the words of M.J.C. Vile, ‘in modern times, been the most significant, both intellectually and in terms of its influence upon institutional structures’.

Vile's classic description of what he calls the ‘pure doctrine’ of the separation of powers offers us an extensive, but still useful definition to serve as a backdrop for the historical development and practical implementations of this idea: ‘It is essential for the establishment and maintenance of political liberty that the government be divided into three branches or departments, the legislature, the executive, and the judiciary . To each of these three branches there is a corresponding identifiable function of government, legislative, executive, or judicial. Each branch of the government must be confined to the exercise of its own function and not allowed to encroach upon the functions of the other branches. Furthermore, the persons who compose these three agencies of government must be kept separate and distinct (…). In this way each of the branches will be a check to the others and no single group of people will be able to control the machinery of the state.’

The lineage of this idea, which for better or for worse has been prominently featured in western thinking on constitution and government for over three-and-a-half centuries, can be traced back to Greek antiquity where, in the works of Aristotle, among others, rudimentary concepts of differentiated governmental functions are distinguished. These do not, however, fully match later notions of a tripartite division of legislative, executive and judicial power, if only because the law, once created, was considered to be more or less fixed.