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Doctrine of the Separation of Powers

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Source: A chapter in Vile's Constitutionalism and the Separation of Powers (2nd ed.) (Indianapolis, Liberty Fund 1998).

ONE. The Doctrine of the Separation of Powers and Institutional Theory

The history of Western political thought portrays the development and elaboration of a set of values—justice, liberty, equality, and the sanctity of property—the implications of which have been examined and debated down through the centuries; but just as important is the history of the debates about the institutional structures and procedures which are necessary if these values are to be realized in practice, and reconciled with each other. For the values that characterize Western thought are not self-executing. They have never been universally accepted in the societies most closely identified with them, nor are their implications by any means so clear and unambiguous that the course to be followed in particular situations is self-evident. On the contrary, these values are potentially contradictory, and the clash of interests to be found in the real world is so sharp that the nature of the governmental structures through which decisions are arrived at is critically important for the actual content of these decisions. There has therefore been, since earliest times, a continuous concern with the articulation of the institutions of the political system, and with the extent to which they have promoted those values that are considered central to the “polity.”

Western institutional theorists have concerned themselves with the problem of ensuring that the exercise of governmental power, which is essential to the realization of the values of their societies, should be controlled in order that it should not itself be destructive of the values it was intended to promote. The great theme of the advocates of constitutionalism, in contrast either to theorists of utopianism, or of absolutism, of the right or of the left, has been the frank acknowledgment of the role of government in society, linked with the determination to bring that government under control and to place limits on the exercise of its power. Of the theories of government which have attempted to provide a solution to this dilemma, the doctrine of the separation of powers has, in modern times, been the most significant, both intellectually and in terms of its influence upon institutional structures. It stands alongside that other great pillar of Western political thought—the concept of representative government—as the major support for systems of government which are labelled “constitutional.” For even at a time when the doctrine of the separation of powers as a guide to the proper organization of government is rejected by a great body of opinion, it remains, in some form or other, the most useful tool for the analysis of Western systems of government, and the most effective embodiment of the spirit which lies behind those systems. Such a claim, of course, requires qualification as well as justification. The “doctrine of the separation of powers” is by no means a simple and immediately recognizable, unambiguous set of concepts. On the contrary it represents an area of political thought in which there has been an extraordinary confusion in the definition and use of terms. Furthermore, much of the specific content of the writings of earlier centuries is quite inappropriate to the problems of the mid twentieth century. The doctrine of the separation of powers, standing alone as a theory of government, has, as will be demonstrated later, uniformly failed to provide an adequate basis for an effective, stable political system. It has therefore been combined with other political ideas, the theory of mixed government, the idea of balance, the concept of checks and balances, to form the complex constitutional theories that provided the basis of modern Western political systems. Nevertheless, when all the necessary qualifications have been made, the essential ideas behind the doctrine remain as vital ingredients of Western political thought and practice today. To substantiate this view it will be necessary to attempt to define and use terms in a more precise way than has been generally the case in the past, and to review the evolution and history of the doctrine, important enough in itself, in order to understand its significance in the past and its relevance today. In spite of the criticisms which can be made of the idea of the separation of powers, perhaps the most important conclusion to be drawn from such a review is that the problems of earlier centuries remain the problems of today; although the context is different, and the dimensions of the problem have changed, it is nevertheless the continuity of political thought, and of the needs of political man, which emerges as the most striking aspect of the history of institutional thought.

The doctrine of the separation of powers finds its roots in the ancient world, where the concepts of governmental functions, and the theories of mixed and balanced government, were evolved. These were essential elements in the development of the doctrine of the separation of powers. Their transmission through medieval writings, to provide the basis of the ideas of constitutionalism in England, enabled the doctrine of the separation of powers to emerge as an alternative, but closely related, formulation of the proper articulation of the parts of government. Yet if we define the doctrine in the terms suggested below, it was in seventeenth-century England that it emerged for the first time as a coherent theory of government, explicitly set out, and urged as the “grand secret of liberty and good government.”1 In the upheaval of civil war the doctrine emerged as a response to the need for a new constitutional theory, when a system of government based upon a “mixture” of King, Lords, and Commons seemed no longer relevant. Growing out of the more ancient theory, the doctrine of the separation of powers became both a rival to it, and also a means of broadening and developing it into the eighteenth-century theory of the balanced constitution. Thus began the complex interaction between the separation of powers and other constitutional theories which dominated the eighteenth century. In England, France, and America this pattern of attraction and repulsion between related yet potentially incompatible theories of government provided the fabric into which was woven the varied combinations of institutional theories that characterized the thought of these countries in that eventful century. The revolutionary potentialities of the doctrine of the separation of powers in the hands of the opponents of aristocratic privilege and monarchical power were fully realized in America and France, and its viability as a theory of government was tested in those countries in a way which all too clearly revealed its weaknesses. Nevertheless, the separation of powers, although rejected in its extreme form, remained in all three countries an essential element in constitutional thought, and a useful, if vague, guide for institutional development. That this once revolutionary idea could also become in the course of time a bulwark of conservatism, is understandable, for this is the fate of many political ideas.

As the nineteenth century developed the social environment became less and less favourable for the ideas which had been embodied in the pure doctrine of the separation of powers. The attack upon the doctrine came in two waves. First, the group which in earlier years had most fervently supported the separation of powers, the middle class, now saw within its reach the control of political power through the extension of the franchise, and the need for a theory that was essentially a challenge to the power of an aristocracy diminished. However, the lessened enthusiasm for the doctrine took the form, in the period up until the Second Reform Act in England, of a re-examination and reformulation of the doctrine rather than an outright rejection of it. Any suggestion of an extreme separation of powers had to be denied, but the importance of the idea as a part of the newly emerging theory of parliamentary government was readily acknowledged. The idea of balance, which was now transferred from the earlier theory of the balanced constitution to become an integral part of the new theory, required still a separation of organs and functions, but with a different set of concepts that had to be fitted into the framework of constitutional theory. The second wave of attack upon the doctrine of the separation of powers came with what Dicey labelled “the age of collectivism.” Yet paradoxically it was the middle-class defenders of the mid-nineteenth-century status quo who, for reasons which will become apparent at a later stage, laid the ground for the virtual eclipse of the separation of powers as a coherent doctrine in England. The rise and fall of the classical theory of parliamentary government is, therefore, an integral part of the story of the separation of powers. At the centre of this development stands the figure of Walter Bagehot, whose work represents a turning-point in the history of English constitutional thought.

Changing ideas about the role of government and its structure were accompanied by a changing emphasis in ideas about the nature of sovereignty. In earlier centuries the stress upon the necessity of a single, omnipotent source of power was in general the resort of theorists of absolutism, strongly rejected by liberal constitutionalists. The defenders of liberty against arbitrary government stressed the division of power, and the limitations upon power imposed by the constitution or by a higher law. Rousseau’s association of the idea of unlimited sovereignty with the people, rather than with a monarch, led, however, to a reorientation of ideas. If absolute power were in the hands of the people, or their representatives, then it could be stripped of its associations with arbitrary government and formed into an instrument of democratic power. If the franchise could be restricted to those with a stake in the community then the idea of an unlimited, indivisible sovereign power became for the liberal individualist not a threat, but a safeguard. It became, in the hands of Bentham and Austin, not a means of arbitrary rule but an instrument for the reform of government which would increase the freedom of the individual. That it could equally well become the instrument of another class, and of a different philosophy of government, was a possibility that, if they acknowledged it, did not prevent them from attacking the earlier ideas of the division and limitation of power. It is one of the great ironies of intellectual history that those who were most concerned to establish laissez-faire busied themselves with the fashioning of those weapons which were to be used most powerfully to destroy it.

The general context of political development during the nineteenth and early twentieth centuries provided, therefore, the framework for a sharp reappraisal of the doctrine of the separation of powers, but there were other equally important, and related, intellectual challenges to the doctrine. The desire for a unified system of government, whether to achieve reform or for purposes of positive State action, led to a rediscovery of the role of discretion and prerogative in government. The idea of a “mere executive power” which had never been wholly accepted in England, except by extreme radicals, was now specifically rejected. The attack upon the Montesquieu formulation of the triad of government powers, initiated by Bentham and Austin, was taken up by the writers on parliamentary government, and further developed in Germany, France, and America, so that by the early decades of the twentieth century the beautiful simplicity of the eighteenth-century view of the functions of government lay mangled and shattered. And yet, although the attack seemed overwhelming, it was so far a merely negative criticism that no coherent formulation of the structure of government and the articulation of its parts rose up to take the place of the earlier theory. As a result the vocabulary of an earlier age continued in use faute de mieux. It was much more than a problem merely of usage, however, for the persistence of the concepts and terminology of an earlier age reflected the fact that Western society in the mid twentieth century continued to value the ideas which had been an integral part of constitutionalism for three centuries, but wished to modify them in the light of new conditions, and new needs. The result of this critical onslaught was, therefore, to leave unrelated fragments of earlier constitutional theories without a new synthesis to fill the gap.

The realization that the functional concepts of the doctrine of the separation of powers were inadequate to describe and explain the operations of government was heightened by the emerging awareness of the nature of bureaucracy. The impact of Prussian bureaucracy upon the nineteenth-century writers, the establishment of a non-political civil service in England, the dissatisfaction with the spoils system in the United States, and the development of the Weberian theory of bureaucracy, led to a complete reassessment of the “executive” function. Thus the demand for the establishment of “harmony” between legislature and government, which characterized the theory of parliamentary government in Britain and France, and the Progressive movement in the United States, was accompanied by a new “separation of powers”—that between the “political” branches of government and the bureaucracy. The distinction between “Regierung” and “Verwaltung,” or between “politics” and “administration” was, paradoxically, to open a new chapter in the establishment of semi-autonomous branches of government in an age which stressed unity and cohesion.

The credibility of the doctrine of the separation of powers, particularly in the extreme forms that had characterized the Constitution of Pennsylvania in 1776, or the Constitution of France in 1791,2 already diminished by these social and institutional developments, was further undermined by the new approaches to the study of politics which characterized the twentieth century. If not everyone was prepared to relegate the study of political institutions to the sphere of mere “superstructure” that Marxist thought seemed to demand, the new concentration upon the “real forces” of politics, upon economics and class interest, led to a discounting of theories that seemed concerned only with constitutional and legal considerations. The now discarded theory of mixed government had at least had a social basis for its view of a desirable governmental system, whereas the separation of powers had, quite deliberately, been formulated as a constitutional theory devoid of class bias. There was a diminution of belief in the efficacy of constitutional barriers to the exercise of power, and students of politics demonstrated how legal rules could be evaded or employed to produce an effect directly opposite to that intended. A concentration upon the facts of “politics” rather than of law, leading to a concern with political parties and pressure-groups, directed attention away from the role of constitutions in the political system. The general attack upon “political theory,” which suggested that it was merely the expression of opinion or prejudice, tended to depreciate those theories that historically had been strongly empirical in content, along with more metaphysical philosophizing. It was suggested that it was not possible to deduce from a general theory of politics specific unequivocal solutions to particular problems, and that therefore it was probably more fruitful to adopt a pragmatic approach to these individual problems, rather than to attempt wide-ranging generalizations.

The weight of the attack upon the doctrine of the separation of powers was thus seemingly overwhelming. Yet the examination of the history of the doctrine is not merely an academic exercise, of historical interest only. In spite of the attacks upon the form, and upon the content, of the doctrine there is a sense in which the problems the theorists of the separation of powers set out to solve are more than ever critical today. The recognition of the fact that modern society must meet demands unknown in earlier centuries may make the form of the earlier doctrine irrelevant, but the values it represented are still an essential part of the content of “Western democracy.” An examination of the history of the past centuries reveals that for all its inadequacy there is a stubborn quality about the doctrine of the separation of powers. It persistently reappears in differing forms, often in the very work of those who see themselves as its most bitter critics. As will be suggested at a later stage, this is no mere coincidence; it is a recognition of the fact that in some form, a division of power, and a separation of function, lie at the very heart of our systems of government. An idea that finds its roots in ancient constitutionalism, and which in the seventeenth century became a central feature of a system of limited government, has obviously to be reformulated if it is to serve as an instrument of modern political thought, but it can only be rejected altogether if we are prepared to discard also the values that called it into being. The study of the history of constitutional theory can show us, therefore, the extent to which the doctrine remains important, and the extent to which the concepts upon which it rests have become outmoded. The importance of such an investigation hardly needs to be stressed, when we recall that the current institutional structures of two of the three countries with which we are here concerned are overtly based upon the acceptance of the doctrine of the separation of powers; and it will be argued that an approach to the study of British government that rules out all reference to the “separation of powers” is an inadequate one.

But what is “constitutional theory”? It is at once both more than and less than the study of political institutions. It is based upon the assumption that not all States are “constitutional regimes,” for in the constitutional State there must be a set of rules which effectively restrains the exercise of governmental power. “Constitutionalism” consists in the advocacy of certain types of institutional arrangement, on the grounds that certain ends will be achieved in this way, and there is therefore introduced into the discussion a normative element; but it is a normative element based upon the belief that there are certain demonstrable relationships between given types of institutional arrangement and the safeguarding of important values. Thus on the one hand constitutional theory has to grapple with the problems of the existence of nominal or façade constitutions, and on the other with the assumptions implicit in the extreme versions of the modern behaviourist approach, which, with its emphasis upon informal processes, tends to suggest that formal structures have little or no significance.3 It is therefore a type of political theory that is essentially empirical, yet which overtly recognizes the importance of certain values and of the means by which they can be safeguarded. Yet in this respect perhaps constitutionalism and constitutional theory are not so far removed from the general stream of political science as might at first be supposed. In the twentieth century the study of politics has become more empirically oriented, less overtly concerned with the justification of particular patterns of values. Nevertheless, the close relationship between the description and explanation of political institutions and of the justification of the values they reflect is an inescapable one. However strong the urge towards objectivity on the part of the student of politics, it is impossible for his work to be wholly detached from the problem of what is a “just,” “desirable,” or “efficient” political system, for the work must inevitably reveal the values that infuse the politics of the countries he studies and the results which their political systems produce. The more theoretical and general his approach the more likely he is, even if only through the means of classification he adopts, to take up a stance of approval or disapproval. This can be seen very clearly in many modern American works on political science.4 There is, in fact, a complex inter-relationship between the study of political institutions and the justification of particular types of governmental systems.

The doctrine of the separation of powers was for centuries the main constitutional theory which claimed to be able to distinguish the institutional structures of free societies from those of non-free societies. It was by no means a value-free or neutral theory of politics, but it did claim to be based upon a demonstrable empirical proof. In the mid twentieth century, however, the doctrine has largely been rejected, either as a prescription for the creation of an efficient, free system of government suited to modern circumstances, or as a set of concepts which provides a useful vocabulary for the investigation and description of systems of government. Yet little has been offered in place of this relatively coherent body of political doctrine as a framework for the analysis of political systems. Indeed, the modern attempts to provide generalized statements about the articulation of the parts of government depend very heavily upon just those concepts of function and balance which characterized earlier constitutional theories. Clearly, however, the extent to which these earlier constitutional theories concentrated attention upon the formal structures of government, especially upon the formal relationships between executive, legislature, and judiciary, made it impossible to handle effectively the problems of distinguishing nominal from effective constitutions, and failed to give a complete picture of “constitutional government” in operation. A discussion of the nature of a limited government must encompass parties and groups, and the results of behavioural studies, as well as the operation of those structures which have traditionally occupied political theorists. At the same time we must not minimize the importance of these political institutions. The emphasis upon the study of certain aspects of behaviour has been taken, at the extreme, to suggest that “institutions” are merely formal and insignificant pieces of window-dressing, whereas in fact political institutions are the framework of rules within which the actors in political situations must normally operate and which students of behaviour tend to take for granted.

The history of the doctrine of the separation of powers provides a panorama of the complex evolution of an idea, and of the role it has played, and continues to play, in the political systems of Western countries; but, equally important, it helps us better to understand the concepts still in use today in the discussion of government, even though many of the assumptions which originally gave rise to these concepts have changed. We still talk of the legislative function or of the relation between legislation and execution, although the meaning we attach to such concepts is very different from that of earlier ages. To understand the way in which these concepts developed is an essential prerequisite for a critical reappraisal of them, in order more clearly to understand how we can best approach the analysis of political systems. Thus the idea of “function,” an essential element in the doctrine, has given rise to considerable confusion in the past, and has been bitterly attacked, yet it still plays a part in our everyday vocabulary of political analysis. The apparent rejection of the doctrine of the separation of powers cannot hide the fact that many practical problems of twentieth-century government are essentially problems with which the doctrine claimed to deal, and we have seen the emergence of terms such as “quasi-judicial,” “delegated legislation,” or “administrative justice,” which represent attempts to adapt the older categories to new problems. The truth is that we face today serious problems, both in political analysis, and in matters of practical significance in the field of government functions and their division among the agencies of government, as well as in terms of the relationships between these agencies. We are not prepared to accept that government can become, on the grounds of “efficiency,” or for any other reason, a single undifferentiated monolithic structure, nor can we assume that government can be allowed to become simply an accidental agglomeration of purely pragmatic relationships. Some broad ideas about “structure” must guide us in determining what is a “desirable” organization for government.

Yet it is not simply the need to attain an academic “understanding” of the ideas and institutions of contemporary Western society that may lead us to explore the history, and analyse the content, of the doctrine of the separation of powers. For today there are practical problems of the control of government every bit as important and difficult as in the days of Locke, Montesquieu, or the Founding Fathers. Although we may be much more sceptical than they were of constitutional theories which claim to be able to set limits to the exercise of governmental power, nevertheless we cannot merely accept without question the view that the continued concentration of power into the hands of cabinets and presidents is inevitable and cannot be restrained. The concentration of more power into such hands, or of certain sorts of power, may be “inevitable,” given certain assumptions about the military, social, and economic needs of modern societies, but which powers, how much of them, and how they can be effectively limited, are the questions we should be asking. The detail of the theories of constitutionalism may be rejected as no longer applicable, but the ethos of constitutionalism remains; we still believe in “limited government,” but we do not yet see how the limits are to be applied in modern circumstances.

In some ways the modern problems of limiting government power are much more subtle and difficult than those of earlier centuries, when liberal constitutionalists took up the cause of freedom from the exercise of arbitrary power. Today, in the West at least, there are no absolute monarchs wielding an oppressive personal power for their own aggrandizement. If there is a danger, it is rather from a process of erosion than from a direct assault upon liberty. There is no conspiracy of power-hungry men attempting to usurp our governmental systems, and the reaction that is called for from us is not the hysterical denunciation of tyranny. The instruments of the extension of government power, both politicians and civil servants, are sincere men who see merely complex practical problems that have to be solved, and which require strong and efficient government action for their solution. A protagonist of “constitutional government” cannot simply adopt the attitude that such problems must remain unsolved in the cause of “liberty”; indeed the modern liberal constitutionalist is likely to be much embarrassed by the support of many who wish to use the banner of “constitutional liberty” to restrain government action that conflicts with their own programmes, yet who are only too ready to use such governmental power, when they themselves control it, for their own ends. Yet the problem of the control of government remains.

In this work, then, the intention is to examine one great current of constitutional thought, the doctrine of the separation of powers, together with its associated theories of mixed government and checks and balances. The history of the doctrine, fascinating in itself, can tell us much about the forces that gave it birth and shape, and by tracing its various formulations light can be thrown upon the problems with which it has attempted to grapple over the years. Following upon the history of the doctrine, an attempt will be made to analyse its content and to discuss the working institutions of Britain and the United States in the light of this analysis. In this way, it is hoped, we shall be able to disentangle the elements of the doctrine which still have relevance today for the understanding of our political systems, and the value of its recommendations for modern society. Such an investigation may lay the foundation for a wider approach to the discussion of governmental structure of the kind referred to above.

A major problem in an approach to the literature on the doctrine of the separation of powers is that few writers define exactly what they mean by the doctrine, what are its essential elements, and how it relates to other ideas. Thus the discussions about its origin are often confused because the exact nature of the claims being made for one thinker or another are not measured against any clear definition. Some kind of preliminary analysis of the doctrine and its elements is therefore necessary before we step into the vast mass of material that history presents to us. The process of definition of a “pure doctrine” of the separation of powers will of necessity have an arbitrary quality, and no doubt other opinions can be put forward as to what constitutes the “essential doctrine,” on the one hand, and what are modifications of, and deviations from, it, on the other. However, no value judgement is intended in putting forward a particular definition, except to say that it is considered the most useful formulation for the purposes we have in mind. It is labelled the “pure doctrine” simply to indicate that it represents a coherent, interrelated set of ideas, with the complicating factors of related theories removed.

An initial problem in any attempt to make a clear statement of the theory of the separation of powers is the ambiguity which attaches to the word “power” in the literature. It has been used to mean the possession of the ability through force or persuasion to attain certain ends, the legal authority to do certain acts, the “function” of legislating, executing, or judging, the agencies or branches of government, or the persons who compose these agencies. A word that is used in at least five different ways within one context is clearly more of a liability than an asset in any attempt to achieve clear thinking, so that we shall as far as possible avoid its use. Wherever possible in the discussion of the ideas of political writers we shall substitute for the word “power” the appropriate synonym of person, agency, or function, according to the context but, of course, when reporting their views we shall by no means be able to do away with the term altogether. It is also difficult to avoid the use of the word in the sense of an ability, through force or influence, to achieve certain ends, and we shall use it in this sense.

A “pure doctrine” of the separation of powers might be formulated in the following way: 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, no individual being allowed to be at the same time a member of more than one branch. 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.

This stark, extreme doctrine we shall then label the “pure doctrine,” and other aspects of the thought of individual writers will be seen as modifications of, or deviations from, it. It is true, of course, that the doctrine has rarely been held in this extreme form, and even more rarely been put into practice, but it does represent a “bench-mark,” or an “ideal-type,” which will enable us to observe the changing development of the historical doctrine, with all its ramifications and modifications, by referring to this constant “pure doctrine.” We shall not go as far as to say that only a thinker who fully subscribes to the above formulation is a “separation of powers theorist,” for this would exclude most of those who have written on the subject and whose intentions were closely in line with the general ethos of the doctrine, but clearly all these elements must be present to some extent for a writer to be considered in this category. Many writers have of course contributed to the development of the theory by evolving one or more elements of it, without being separation of powers theorists—indeed, whilst rejecting the doctrine. Thus the idea of the functions of government has been evolved in large part by the theorists who implicitly or explicitly rejected other essential elements of the doctrine.

The first problem presented by the theory outlined above is its commitment to “political liberty,” or the exclusion of “arbitrary power.” Clearly the viability of the whole approach may turn upon the definition of liberty chosen. Thus perhaps one of the most persuasive general criticisms of the doctrine is that it has been associated with an essentially negative view of political liberty, one too concerned with the view of freedom as absence of restraint, rather than with a more positive approach to freedom. The concern to prevent the government from encroaching upon individual liberty leads to measures which weaken it to the point where it is unable to act in order to provide those prerequisites of social and economic life which are essential if an individual is to be able to make proper use of his faculties. The decline in the popularity of the doctrine in the twentieth century, both in the United States and in Britain, is closely related to the recognition of the need for “collectivist” activities on the part of government, which require a co-ordinated programme of action by all parts of the government machine. The doctrine of the separation of powers is clearly committed to a view of political liberty an essential part of which is the restraint of governmental power, and that this can best be achieved by setting up divisions within the government to prevent the concentration of such power in the hands of a single group of men. Restraints upon government are an essential part of the view of political liberty enshrined in this approach, but we shall have to consider the extent to which the proponents of the doctrine also recognized that a minimum degree of “strong government” was also necessary to political liberty, and the possible ways in which the tenets of the doctrine are compatible with the minimum needs of government action in the twentieth century. Indeed it will be assumed that the recognition of the need for government action to provide the necessary environment for individual growth and development is complementary to, not incompatible with, the view that restraints upon government are an essential part of a theory of political liberty.

The first element of the doctrine is the assertion of a division of the agencies of government into three categories: the legislature, the executive, and the judiciary. The earliest versions of the doctrine were, in fact, based upon a twofold division of government, or at any rate upon a twofold division of government functions, but since the mid eighteenth century the threefold division has been generally accepted as the basic necessity for constitutional government.5 We may not today take the scriptural authority that John Sadler in 1649 propounded as the basis for a threefold division—“And why may not the Sacred Trinity be shaddowed out in Bodies Politick, as well as in Naturall?”6 —but something of a mystical quality seems still to surround this method of organizing the agencies of government. In the eighteenth century the idea of a balance or equilibrium in the system of government which depended upon the ability of any two of King, Lords, and Commons being able to prevent the third from exceeding the proper limits of its power, provided a basis for the idea, at any rate, of an odd number, rather than an even number, of governmental agencies, but today such a justification seems to have disappeared entirely,7 and in fact it is often difficult to force the manifold agencies of a modern system of government into these three categories. Nevertheless this division does reflect important, continuing elements in liberal democratic theory. The growth of three separate branches of the government system in Britain reflected in part the needs of the division of labour and specialization, and partly the demand for different sets of values to be embodied in the procedures of the different agencies, and in the representation of varying interests in the separate branches. This aspect of the doctrine, although usually assumed by political theorists rather than explicitly developed, is clearly central to the whole pattern of Western constitutionalism. The diffusion of authority among different centres of decision-making is the antithesis of totalitarianism or absolutism. Thus in the totalitarian State every aspect of the State machine is seen merely as an extension of the party apparatus, and subordinate to it. A continuous effort has to be made to prevent any division of the machine from developing its own interest, or from creating a degree of autonomy in the taking of decisions. In practice the pressures which operate against this attempt to maintain a single monolithic structure are too strong, for the price in inefficiency which has to be paid is too high, and of necessity rival centres emerge in the bureaucracy and in industry or elsewhere. But the “ideal” of the totalitarian state is that of a single all-embracing agency of government.

The “separation of agencies,” therefore, is an essential element in a theory which assumes that the government must be checked internally by the creation of autonomous centres of power that will develop an institutional interest. Without the other elements of the doctrine of the separation of powers being present we might still expect some limitation on the ability of a single group to dominate the government if separate agencies are established. Even if the personnel of the agencies overlap, powerful influences may arise to create divergences of interest within the government. Differing procedures introduce differing values and different restraints; the emergence of an “institutional interest,” the development of professionalism, the influence of colleagues and traditions, all provide the possibility, at least, of internal checks. Separate agencies, composed of distinct bodies of men even where functions are shared can be made representative of different groups in the community, and so, as with bicameral legislatures, provide the basis of a check upon the activities of each of them.

The second element in the doctrine is the assertion that there are three specific “functions” of government. Unlike the first element, which recommends that there should be three branches of government, this second part of the doctrine asserts a sociological truth or “law,” that there are in all governmental situations three necessary functions to be performed, whether or not they are in fact all performed by one person or group, or whether there is a division of these functions among two or more agencies of government. All government acts, it is claimed, can be classified as an exercise of the legislative, executive, or judicial functions. The recommendation then follows that each of these functions should be entrusted solely to the appropriate, or “proper,” branch of the government. This view of the “functions” of government is extremely abstract, and some of the attempts to justify this threefold division have reached a very high degree of abstraction indeed. It must be distinguished from the very different view of the functions of government which enumerates them as, for example, the duty of keeping the peace, of building roads, or of providing for defence. These we might label the “tasks” of government in order to distinguish them from the more abstract notion of function. In the period before Locke and Montesquieu firmly established this abstract view of the functions of government there were two main streams of thought, in one of which the word “power” was used to describe the function of legislating, or executing the law, and in the other a more practical view was taken of the multiplicity of government acts by dividing up the “attributes of sovereignty” into six, seven, or more categories, which included, as well as making laws, such tasks as the control of the coinage, or the appointment of standard weights and measures.8 The triumph of the more abstract conception of the “powers” or functions of government in the eighteenth century, and its later development and ramification, was of great importance for the way in which later writers approached the problems of government structure. In the twentieth century this view of the nature of the functions of government has been subjected to severely critical analysis, but the vocabulary of the doctrine still dominates our everyday usage and our way of thinking about the nature of the operations of government.

The third element in the doctrine, and the one which sets the separation of powers theorists apart from those who subscribe to the general themes set out above but are not themselves advocates of the separation of powers, is what, for want of a better phrase, we shall describe as the “separation of persons.” This is the recommendation that the three branches of government shall be composed of quite separate and distinct groups of people, with no overlapping membership. It is perfectly possible to envisage distinct agencies of government exercising separate functions, but manned by the same persons; the pure doctrine here argues, however, that separation of agencies and functions is not enough. These functions must be separated in distinct hands if freedom is to be assured. This is the most dramatic characteristic of the pure doctrine, and is often in a loose way equated with the separation of powers. The final element in the doctrine is the idea that if the recommendations with regard to agencies, functions, and persons are followed then each branch of the government will act as a check to the exercise of arbitrary power by the others, and that each branch, because it is restricted to the exercise of its own function will be unable to exercise an undue control or influence over the others. Thus there will be a check to the exercise of the power of government over “the people” because attempts by one branch to exercise an undue degree of power will be bound to fail. This is, of course, the whole aim and purpose of the doctrine, but it is just here that the greatest theoretical difficulty is to be found; and as a result what we have termed the pure doctrine has therefore been modified by combining it with some rather different doctrine to produce a complex amalgam of ideas about the limitations to be placed upon government authorities. The pure doctrine as we have described it embodies what might be called a “negative” approach to the checking of the power of the agencies of government. The mere existence of several autonomous decision-taking bodies with specific functions is considered to be a sufficient brake upon the concentration of power. Nothing more is needed. They do not actively exercise checks upon each other, for to do so would be to “interfere” in the functions of another branch. However, the theory does not indicate how an agency, or the group of persons who wields its authority, are to be restrained if they do attempt to exercise power improperly by encroaching upon the functions of another branch. The inadequacy of the controls which this negative approach to the checking of arbitrary rule provides, leads on to the adaptation of other ideas to complement the doctrine of the separation of powers and so to modify it.

The most important of these modifications lies in the amalgamation of the doctrine with the theory of mixed government, or with its later form, the theory of checks and balances. The connections between these theories will be examined more fully in the ensuing chapters; from an analytical point of view the main consideration is that these theories were used to import the idea of a set of positive checks to the exercise of power into the doctrine of the separation of powers. That is to say that each branch was given the power to exercise a degree of direct control over the others by authorizing it to play a part, although only a limited part, in the exercise of the other’s functions. Thus the executive branch was given a veto power over legislation, or the legislative branch was given the power of impeachment. The important point is that this power to “interfere” was only a limited one, so that the basic idea of a division of functions remained, modified by the view that each of the branches could exercise some authority in the field of all three functions. This is the amalgam of the doctrine of the separation of powers with the theory of checks and balances which formed the basis of the United States Constitution. Related to this, and to its predecessor in time, is an amalgam of the doctrine of the separation of powers with the theory of mixed government to produce a partial separation of functions. That is to say that one function, the legislative, was to be shared, but other functions were to be kept strictly separate. This was a basic element in eighteenth-century English constitutionalism, the theory of balanced government. These modifications of the doctrine have of course been much more influential than the doctrine in its pure form.

The idea of a partial separation of functions is an important one, for it does not cease to be significant simply because it is partial. We shall consider the objections made against Montesquieu, for example, on the grounds that he did not believe in the separation of powers because he gave to the branches of government certain powers over each other which amounted to a participation in the exercise of the functions of another branch. But Montesquieu did not give each branch an equal part to play in the exercise of each function of government—far from it; he set up a basic division of functions and then imposed certain control mechanisms upon this fundamental division. A similar modification of the pure doctrine can be seen in the area of the separation of persons. The pure doctrine demands the complete separation of the personnel of the three branches of government, but this can be modified to introduce a partial separation of persons. That is to say that some people may be allowed to be members of more than one branch of the government, although a complete identity of personnel in the various branches will be forbidden. Again, as with the separation of functions, such an approach does not mean that the idea of the separation of powers has been wholly jettisoned. The degree of separation will become important. How many people are to be allowed to be members of more than one branch, who will they be, and what will be their function and authority? The answers given to these questions in the mid nineteenth century provided the basis of the parliamentary system of government. Thus we can see the pure doctrine as an ideal for an extreme separation of “powers,” but we can then introduce various modifications and discuss their effects, and try to determine the points at which the doctrine no longer plays a significant part in the resulting amalgam.

Two further concepts must be mentioned which have not figured to any great extent in the literature on the separation of powers, but whose relation to the doctrine is of great importance. The first, an extremely ancient concept, is the idea of procedure as a check to the exercise of power. The belief that “due process” is an essential part of constitutional government is of great antiquity, and it runs parallel with ideas of mixed government and the separation of powers, but has relatively rarely been explicitly linked with those ideas and made an integral part of those theories. The second notion, a much more modern one, is the idea of process in government. This term, although used in different ways, indicates an awareness that government and politics do not consist in the automatic operation of formal procedures, but that there is a whole complex of activities around these procedures which determines the exact way in which they will be operated, sometimes in fact bringing about through the medium of the procedure exactly the reverse of what the procedure was intended to achieve. The concern of political studies with the role which political parties and groups play in the processes of government makes it impossible any longer to discuss a theory like that of the separation of powers purely in terms of the more formal, legal institutions of government. If the theory has anything to offer it must be able to cope with the complexities of “politics” as well as the structure of governments.

The long history of the doctrine of the separation of powers reflects the developing aspirations of men over the centuries for a system of government in which the exercise of governmental power is subject to control. It illustrates how this basic aspiration towards limited government has had to be modified and adapted to changing circumstances and needs. It offers a rich mass of material, of human thought and experience, on a subject which remains today a matter of vital importance. To follow the course of this history should be of interest in itself, but it is also an essential step towards the understanding of the ideas of the past which have helped to shape our own, and towards the reformulation of these ideas into a more coherent theoretical approach to the nature of modern constitutional government.

[1. ]A True State of the Case of the Commonwealth, London, 1654, p. 10; see below, pp. 53–57.

[2. ]The role of the separation of powers in these Constitutions is discussed in Chs. 6 and 7 below.

[3. ]See the discussion by Giovanni Sartori, “Constitutionalism: A Preliminary Discussion,” A.P.S.R., Vol. LVI, No. 4, Dec. 1962.

[4. ]See the discussion of Almond and Coleman, The Politics of the Developing Areas, in Ch. 10 below.

[5. ]As far as the actual institutional development is concerned, of course, the basis of the threefold structure had been laid in England by the thirteenth century. See F. W. Maitland, The Constitutional History of England, Cambridge, 1961, p. 20; see also E. Klimowsky, Die englische Gewaltenteilungslehre bis zu Montesquieu, Berlin, 1927.

[6. ]Rights of the Kingdom, London, 1649, p. 86.

[7. ]The connection between the theories of mixed government, of the balanced constitution, and the emergence of the threefold separation of powers is discussed in Ch. 3.

[8. ]See Ch. 2 below.

Last modified April 10, 2014