Montesquieu and the Separation of Powers

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Source: M.J.C. Vile's Chapter 4 in Constitutionalism and the Separation of Powers (2nd ed.) (Indianapolis, Liberty Fund 1998).


The name most associated with the doctrine of the separation of powers is that of Charles Louis de Secondat, Baron Montesquieu. His influence upon later thought and upon the development of institutions far outstrips, in this connection, that of any of the earlier writers we have considered. It is clear, however, that Montesquieu did not invent the doctrine of the separation of powers, and that much of what he had to say in Book XI, Chapter 6 of the De l’Esprit des Loix was taken over from contemporary English writers, and from John Locke.1 Montesquieu, it is true, contributed new ideas to the doctrine; he emphasized certain elements in it that had not previously received such attention, particularly in relation to the judiciary, and he accorded the doctrine a more important position than did most previous writers. However, the influence of Montesquieu cannot be ascribed to his originality in this respect, but rather to the manner and timing of the doctrine’s development in his hands.

Long before the publication of De l’Esprit des Loix Montesquieu had become widely known and respected through the publication of the Lettres persanes and the Considérations sur les causes de la grandeur des Romains. The appearance of his great work was awaited with impatience, and, once published, it quickly ran through several editions. When the work appeared it was clearly not a piece of transient political propaganda, as had been many of the writings we have so far surveyed—it was the result of twenty years of preparation, and was intended as a scientific study of government, encompassing the whole length and breadth of history, and accounting for all the factors affecting the political life of man. Montesquieu, in his Preface, made it clear what the work contained:2 “I have laid down the first principles, and have found that the particular cases follow naturally from them; that the histories of all nations are only consequences of them; and that every particular law is connected with another law, or depends on some other of a more general extent.” These principles are not drawn from the writer’s prejudices, but “from the nature of things.” Montesquieu intends to show the way in which the laws of each State are related to the nature and principles of its form of government, to the climate, soil, and economy of the country, and to its manners and customs.3 Such a scientific approach rules out the expression of personal likes and dislikes: “Every nation will here find the reasons on which its maxims are founded.” No absolute solutions are proposed, only the necessary relationships between the form of government and the laws are exposed. This claim to scientific detachment gives to Montesquieu’s work a status that no political pamphleteer could claim. The doctrine of the separation of powers is embedded in this examination of cause and effect in the political system. It is no longer an isolated doctrine, taken up when political advantage makes it expedient, and put off when no longer needed; it is part of the relationships of a particular type of legal system; and furthermore, it is a necessary characteristic of that system which has political liberty as its direct aim. De l’Esprit des Loix was hailed as the first systematic treatise on politics since Aristotle; not a desiccated, boring treatise for the expert alone, but rather as a work the brilliant style of which made it an object of attention for all educated men. Indeed, Voltaire caustically remarked that it was Montesquieu’s style alone which retrieved a work so full of error.4

De l’Esprit des Loix was published in 1748, and so became available at the beginning of a period of great change and development in Europe and America. Ideas which had blossomed in the English Civil War, but which had been premature and unrealistic in terms of the then existing society, could now find fertile ground in the British colonies of North America and in France. Within the next fifty years men were to be called upon to create new institutions, to attempt to establish new systems of government. Where better look for help than in a manual where the principles of all governments were set out, and where none were more sympathetically treated than those forms of government that set bounds to the exercise of arbitrary power. For although Montesquieu claimed to be disinterested, his affection for moderate government shines through the whole work, whether it be a moderate monarchy or a moderate republic he is describing. But Montesquieu’s approach did lead to a good deal of confused speculation about his own loyalties. Was he advocating monarchy as the best system of government, or did he believe in a mixed system, or was he a good republican? Evidence for all these points of view can be found in his great work, and, indeed, it was the very fact that the De l’Esprit des Loix can be pressed into service in support of widely differing views that added to its influence. By the end of the eighteenth century Montesquieu was being quoted as an authority in England, France, and America, as conclusive evidence of the rightness of very different systems of government.

Montesquieu started from a rather gloomy view of human nature, in which he saw man as exhibiting a general tendency towards evil, a tendency that manifests itself in selfishness, pride, envy, and the seeking after power.5 Man, though a reasoning animal, is led by his desires into immoderate acts. Of the English, Montesquieu wrote that “A people like this, being always in ferment, are more easily conducted by their passions than by reason, which never produced any great effect in the mind of man.”6 In the realm of politics this is of the greatest consequence: “Constant experience shows us that every man invested with power is apt to abuse it, and to carry his authority as far as it will go.”7 However, this tendency towards the abuse of power can be moderated by the constitution of the government and by the laws, for, although by no means a starry-eyed utopian, Montesquieu, like the Greeks, believed that the nature of the State’s constitution is of the greatest consequence. Thus Montesquieu commenced his work with a description of the three different types of government, their nature and their principles, for if he could establish these, then the laws would “flow thence as from their source.”8 Let us look at the way in which Montesquieu dealt with this problem of the control of power.

He defined three types of government: republican, monarchical, and despotic. In the first the people is possessed of the supreme power; in a monarchy a single person governs by fixed and established laws; in a despotic government a single person directs everything by his own will and caprice.9 Republican government can be subdivided into aristocracy and democracy, the former being a State in which the supreme power is in the hands of a part of the people, not, as in a democracy, in the body of the people. In a despotic government there can be no check to the power of the prince, no limitations to safeguard the individual—the idea of the separation of powers in any form is foreign to despotic governments. In an aristocracy also, though it be a moderate government, the legislative and executive authority are in the same hands.10 However, in a democracy, Montesquieu argued, the corruption of the government sets in when the people attempt to govern directly and try “to debate for the senate, to execute for the magistrate, and to decide for the judges.”11 Montesquieu implied, then, that some form of separation of powers is necessary to a democracy, but he did not develop this point. The relevance of this to modern states is in any case rather slight, as Montesquieu believed that democracy was only suitable to small societies.12 The most extended treatment he gives of institutional checks to power, therefore, is to be found in his discussion of monarchy and of the English Constitution. These two discussions, though obviously connected in spirit, seem to be drawn from quite different sources, and to depend upon different principles. Each system is praised for its virtues, but it is difficult to say that Montesquieu clearly favoured one above the other. Here we have the source of the confusions on this subject.

The different elements in Montesquieu’s approach to the control of power can be attributed to his two major sources of inspiration. On the one hand the influence of English writers, especially Locke and Bolingbroke, is clear.13 From the time of the Civil War onwards the volume of translations of English works on politics, and of French commentaries on England, had grown, until in the early eighteenth century it reached large proportions. Dedieu points to the importance of the exiled Huguenot journalists, lauding the virtues of the Glorious Revolution, to the writings of anglophile Frenchmen, and to the work of historians who emphasized the role of the English Parliament as a balance to the power of the Crown.14 In particular Rapin-Thoyras, in his Histoire d’Angleterre in 1717, emphasized the importance of a balanced constitution and mixed government. Voltaire in 1734 published a French edition of his English Letters, in which he wrote of the “mélange dans le gouvernement d’Angleterre, ce concert entre les Communes, les Lords et le Roy.”15 These, together with Montesquieu’s travels in England, his acquaintance with Bolingbroke, and his knowledge of the writings in the Craftsman, the paper for which Bolingbroke wrote,16 are the sources of the main ideas to be found in his chapter on the English Constitution.

There are other sources, nearer at home, however, for Montesquieu’s attitude towards monarchy. Here, as in his description of the English Constitution, Montesquieu was concerned with the control of arbitrary power, but in a different way, and in a different context. As an aristocrat, and président à mortier of the parlement of Bordeaux, he could look back upon a long tradition of French resistance to the idea of despotism, not along the lines of the English developments, but in terms of the power of the parlements, and of the aristocracy and clergy of France as checks upon the royal authority.17 Bodin, though asserting the indivisibility of the sovereign power of the King, nevertheless had advocated that the parlements should have the power of remonstrance and of enregistering royal enactments, so that they might judge these in the light of justice and equity.18 The parlements had from time to time asserted their right to refuse to register royal edicts, especially the parlement of Bordeaux, of which Montesquieu later became a président à mortier.19 Boulainvilliers in 1727 had argued that all the unhappiness of France was due to the way in which the nobility had declined in power, and it was in defence of a similar thesis that Montesquieu approached the problem of the French monarchy.20 Thus when Montesquieu defined monarchy, as opposed to despotism, as a system in which “intermediate, subordinate, and dependent powers” played an essential role, and named these intermediate powers as the nobility, the clergy, and the parlements, he was following a well-trodden path in French thought.

It is Bodin, however, more than any other thinker, who would seem to have provided the pattern for Montesquieu’s idea of monarchy; and if this is so, it is of great importance, for Bodin’s views on sovereignty are bound to colour the whole nature of the approach to the monarchical system.21 Bodin had, it is true, been concerned to champion a strong monarchy, and to stress the concentration of power in the hands of the monarch, but he also stressed the difference between a tyranny and a “royal” or “legitimate” monarchy. The latter is one in which the king “yieldeth himself as obedient unto the laws of nature as he desireth his subjects to be towards himselfe, leaving unto every man his naturall libertie, and the proprietie of his own goods.”22 He accorded a role in the government, even if only a subordinate one, to the States-General and the parlements. The pattern of Bodin’s royal monarchy is very close to Montesquieu’s view of monarchy, and there is little evidence to suggest that the latter saw any real modification in the structure of this form of government that would approximate to a “separation of powers.” It is true that Montesquieu writes that to form a “moderate government,” which of course includes monarchy, it is “necessary to combine the several powers; to regulate, temper, and set them in motion; to give, as it were, ballast to one, in order to enable it to counterpoise the other.”23 However, it is difficult to place much weight upon this statement as an indication of Montesquieu’s belief in a “separation of powers” in a moderate government, for as it stands it applies also to aristocracy, which Montesquieu specifically characterizes as a system in which the legislative and executive powers are in the same hands, and there is no other indication of a belief in the separation of powers in a “monarchy.” On the contrary, Montesquieu clearly asserted the indivisibility of the supreme power in the hands of the monarch,24 and the subordination of the “intermediary powers.”25 We must, therefore, see Montesquieu’s moderate monarchy as governed by law, but not as a limited monarchy in the English sense, nor as a system of mixed government or the separation of powers.

Monarchy for Montesquieu was government by the law, through the recognized channels by which the royal power must flow. The idea of a separation of agencies and functions, in part at least, is implicit and explicit in his treatment of monarchy. The judges must be the depository of the laws; the monarch must never himself be a judge, for in this way the “dependent intermediate powers” would be annihilated.26 The king’s ministers ought not to sit as judges, because they would lack the necessary detachment and coolness requisite to a judge.27 There must be many “formalities” in the legal process in a monarchy in order to leave the defendant all possible means of making his defence,28 and the judges must conform to the law.29 In the monarchy, then, power is exercised in a controlled way, but it is not the separation of powers in the sense in which we have used this term, at any rate as far as the legislative and executive powers are concerned. There is considerable emphasis upon the role of the judges, but “the prince is the source of all power,” and he clearly exercises both the legislative and executive powers within the fundamental constitution.30 The checks upon the royal power operate as a result of the existence of the various orders of society through which that power must be channelled, but these “intermediate powers” do not even include a body of representatives of the people. The people’s safeguard is in the principle of monarchy, honour, which, by definition, infuses the rule of the monarch over his people.31 This, then, is what Montesquieu seems to have considered best for France; it is the ancestral constitution that had been for a time subverted, a constitution in which the King did not exercise a capricious and arbitrary power, but not a constitution that can be described as embodying the separation of powers. Indeed we must not be confused by the terminology Montesquieu uses. Undoubtedly today his “monarchy” would be described as a despotism, if a benevolent one. His constitutional monarch was in the tradition of French, not English, thought. It certainly is not the monarchy that the seventeenth-century constitutional battles produced in England. Even Charles I could hardly have hoped that a King of England would exercise the power Montesquieu accords his monarch.32

When we turn from the description of the monarchy to the discussion of the English Constitution we must first consider two difficulties. What were Montesquieu’s views on mixed government, and what form of government did he believe England to have? Montesquieu’s treatment of mixed government is characteristic of the problems of interpretation he presents. At the beginning of his work, when enumerating the types of government, he did not consider mixed government at all. There is no direct mention of this idea which had been so important in English political thought for centuries, and which had also figured in the work of Hotman and others in France. Montesquieu writes of “moderate” governments, but these are the uncorrupted forms of monarchy and republic. At one point he seems to be saying that a mixed constitution is impossible, or at least that he knows of none that exists.33 Again the parallel with Bodin is striking. When Montesquieu turns in Book XI to his discussion of England, however, he adopts a very different approach.

In this form of government the executive power should be in the hands of a monarch, and the legislative power committed to the body of the nobles and to that body which represents the people, “each having their assemblies and deliberations apart, each their separate views and interests.”34 This is the fundamental constitution of a free state: “The legislative body being composed of two parts, they check one another by the mutual privilege of rejecting. They are both restrained by the executive power, as the executive is by the legislative.” Montesquieu immediately follows this sentence with a reference to “these three powers,” by which he seems to mean King, Lords, and Commons, not legislature, executive, and judiciary. This is clearly a system of mixed government, and in the rest of Book XI Montesquieu refers to mixed systems in glowing terms, whether in reference to the Gothic constitutions of Europe, or to the harmony of power in the government of Rome when it consisted of a mixture of monarchy, aristocracy, and democracy.35 How do we reconcile these references with the earlier chapters of the work? One answer, perhaps, is simply to say that they are irreconcilable and leave it at that. Montesquieu drew his inspiration from diverse sources and was unable to integrate all his ideas into a single theoretical framework. It is hardly surprising that he failed to reconcile completely the two models of government that he drew from Bodin and from Bolingbroke. A rather different approach is to view Montesquieu’s descriptions of despotism, monarchy, and republic as “ideal types” to which governments in practice would only imperfectly conform, so that imperfect examples of actual governments might contain elements of more than one type. There is some evidence that Montesquieu was thinking in this way. For example he writes: “The nearer a government approaches towards a republic, the more the manner of judging becomes settled and fixed.”36 And in Book VIII, where he discusses the way in which the principles of the three forms of government can be corrupted, he clearly envisages that States can exist that only imperfectly conform to the principles of these three forms. Again, reference to Bodin may help us here. Bodin tells us that his three forms of commonwealth are “ideal types.”37 He rejects altogether the idea of a mixed form of State, because of the logical and practical impossibility of the division of the sovereign power; but he distinguishes between forms of State and forms of government, allowing that the form of government may differ from the form of State in which it operates, so that a monarchy may, in reality, operate as an aristocracy or democracy, and also that combinations of forms of government are possible.38 Montesquieu seems to view England in this light. Thus he refers to it as “a nation that may be justly called a republic, disguised under the form of a monarchy”;39 and again, he says that England “having been formerly subject to an arbitrary power, on many occasions preserves the style of it, in such a manner as to let us frequently see upon the foundation of a free government the form of an absolute monarchy.”40

However, the problem is further complicated by the view that, in Book XI, Chapter 6, Montesquieu was creating an ideal type of a “constitution of liberty,” with England as its source, but that he was not describing the English Constitution as it actually existed. When Montesquieu wrote of “England” here he was writing of an imaginary country, as in the Lettres persanes:l’Angleterre de Montesquieu c’est l’Utopie, c’est un pays de rêve.41 Thus in certain respects Montesquieu’s statements in this chapter differ considerably from what he actually knew to be the case in England. For example, he writes of the judiciary as if it contained no professional judges, as if juries were judges of both fact and law. The reality of English life was, as Montesquieu himself notes elsewhere, quite different from the ideal situation depicted in XI, 6.42 If, therefore, this chapter also constructs an “ideal type,” we must consider it on its merits, and not concern ourselves with the long controversy over the correctness of Montesquieu’s description of the early-eighteenth-century constitution of England.43 But how does this ideal type relate to his ideal types of monarchy, despotism, and republic? Is it a fourth and quite distinct category, or a sub-category of one of them? These questions are no doubt unanswerable, for they demand from Montesquieu a consistency he does not have. We must accept these inconsistencies, and make the best of them.

This, then, is the framework within which is set the famous chapter on the English Constitution, which has had greater influence than any other part of the De l’Esprit des Loix, the chapter which further evolves the doctrine of the separation of powers. As with all the previous writers we have surveyed, it is still not a “doctrine,” nor does the term “separation of powers” appear in the text, although Montesquieu does assert that liberty is lost if the three powers are not “separated.”44 What does Montesquieu have to say about the separation of powers? A remarkable degree of disagreement exists about what Montesquieu actually did say. Two broad streams of interpretation of his thought since the latter part of the eighteenth century can be detected. One, largely associated with the continent of Europe, and with jurists rather than political theorists, sees what we have called “the pure doctrine of the separation of powers,” a thoroughgoing separation of agencies, functions, and persons. The other, represented principally by the Fathers of the American Constitution, French writers such as Benjamin Constant, and in a rather different way the English commentators of the eighteenth and nineteenth centuries, has seen some form of a partial separation of powers, that is the pure doctrine modified by a system of checks and balances.45 Some writers go further and claim that the term “separation of powers” as applied to Montesquieu’s thought is an exaggeration or misrepresentation, that he was concerned only with the establishment of the “non-confusion” of powers,46 that he was trying to establish only the juridical independence of the legislature and the government and not a separation of functions or persons,47 or that he demanded only the “harmonious integration” of the powers of government.48 Let us take each strand of the doctrine and of the idea of checks and balances in order to assess what Montesquieu has to say in the De l’Esprit des Loix.

Montesquieu’s approach to the definition of the functions of government resembles a review of the history of the uses of these concepts. Chapter 6 of Book XI begins: “In every government there are three sorts of power, the legislative; the executive in respect to things dependent on the law of nations; and the executive in regard to matters that depend on the civil law.” This is clearly a restatement of Locke’s division of government functions, except that Montesquieu does not use the term “federative power” for the executive power in regard to external affairs. He still uses the term “executive” to cover all internal affairs, both governmental and judicial; in other words he adopts, though only momentarily, the twofold division of functions into legislative and executive so familiar to the seventeenth century and earlier. Montesquieu then immediately redefines his terms. He affirms that he intends to use the term “executive power” exclusively to cover the function of the magistrates to make peace or war, send or receive embassies, establish the public security, and provide against invasions. He now seems to wish to confine the term “executive power” to foreign affairs, for he does not make it at all clear that the power to “establish the public security” has any internal connotation—in other words, for Locke’s “federative power” read “executive power.” Furthermore, Montesquieu announces that he will call the third power, by which the magistrate punishes criminals or decides disputes between individuals, the “power of judging.”49 This appears to represent an attempt to reconcile the authority of Locke with the heightened appreciation of the separate existence of the judicial power as distinct from the royal power which had emerged in the early eighteenth century. But this formulation leaves out of account any “executive” acts other than foreign affairs, for the judicial power is confined to disputes between the prince and the individual, and between individuals. Montesquieu has not so far, then, managed to reconcile the seventeenth-century vocabulary with the facts of eighteenth-century government; the vital distinction between the internal acts of the executive and the acts of the judiciary is obscured. However, when he goes on to use these terms he drops both definitions and uses them in a very much more modern way; the three powers are now “that of enacting laws, that of executing the public resolutions, and of trying the causes of individuals,” clearly including internal as well as external affairs in the executive power. It is in this final sense that Montesquieu discusses the relationships between the powers of government, and it is, of course, basically the modern use of these terms. The importance of this transition in his use of words cannot be overemphasized. Not only does he bridge the gap between early modern and later modern terminology, but he also obscures one of the basic problems of a threefold definition of government functions. Locke and others had been bothered by the fact that the “ruler” had two aspects to his function. He had to carry out the law where it was clear and easily stated, principally in internal affairs, but he had also to act in areas where the law could not be laid down in detail and where his prerogative must remain almost wholly untrammelled, that is to say largely in external affairs. Thus between them Locke and Montesquieu state at least four functions of government, not three: the legislative, the executive, the “prerogative,” and the judicial. To bring the two middle ones together as “executive” obscures the fact that in large areas of government activity those responsible for day-to-day government decisions will not be “executing the law,” but exercising a very wide discretion. However, the idea that there are three, and only three, functions of government, was now established, except perhaps in the minds of those English lawyers who had actively to define the prerogative powers of the Crown.

The most important aspect of Montesquieu’s treatment of the functions of government is that he completes the transition from the old usage of “executive” to a new “power of judging,” distinct from the putting of the law into effect, which becomes the new executive function. However, it is in his treatment of the “power of judging” that Montesquieu’s greatest innovatory importance lies. He treats the puissance de juger as on a par, analytically, with the other two functions of government, and so fixes quite firmly the trinity of legislative, executive, and judicial which is to characterize modern thought. Vitally important also is the fact that he detaches this power from the aristocratic part of the legislature and vests it unequivocally in the ordinary courts of the land, although the noble house of the legislature is to have the role of a court of appeal. However, he still does not give the courts the position they were soon to achieve in American thought; he does not accord the judicial branch an exactly equal status with the legislative and executive branches, although he clearly intends the judiciary to be independent of the other two. He sees these two agencies as permanent bodies of magistrates,50 which represent real social forces, the monarch, the nobility, and the people. The judiciary, however, “so terrible to mankind,” should not be annexed to any particular class (état) or profession, and so becomes, in some sense, no social force at all—“en quelque façon nulle”—representing everyone and no one.51 The judiciary, therefore, is to be wholly independent of the clash of interests in the State, and this emphasis upon judicial independence is extremely important for the development of the doctrine.

Montesquieu devotes considerable attention to the nature and composition of the judiciary, but his approach to this problem is very much a reflection of his general scheme, and does not bear much relation to the actual practice in England. In Book VI he had developed his ideas about the judicial function in the differing forms of State. In a despotic government the caprice of the prince is the basis of the law, and judging will be an arbitrary process without rules. In a monarchy, however, the prince rules according to the laws; these must be relatively stable and applied in a cool, aloof fashion. The judges in a monarchy, therefore (and Montesquieu is clearly thinking of the parlements), must be learned in the law, professional, and skilled in the reconciliation of potentially conflicting rules. But the closer the form of government approaches that of a republic, the more fixed and settled are the rules of law, and the more the judges must follow the letter of the law.52 In Rome, he avers, the judges had only to decide matters of fact, and then the punishment was clearly to be found in the laws. In England the jury gives its verdict on the facts and the judge pronounces the punishment inflicted by the law, “and for this he needs only to open his eyes.”53 In Book XI he describes a judicial system without professional judges. He rejects the idea of the judiciary power being lodged in a “standing senate,” and affirms that it should be exercised by persons drawn (tirées) from the people, on an ad hoc basis for fixed periods of short duration. In other words a system of juries, which would apparently be judges of both fact and law, because the laws would be so clear and explicit as to require no professional knowledge in the judges.

Two further aspects of Montesquieu’s treatment of the judiciary require emphasis. First, his insistence that in republics the judges must abide by the letter of the law is of great importance for later views of the judicial function. In England in medieval times the judges were well aware that they “interpreted” the law, and from time to time were aware that they were making law through “interpretation.” The role of the judges in making the law was also recognized in the seventeenth century. But Montesquieu insists that to allow the judges to exercise discretion is to expose the people to the danger that the private opinions of the judges might render the laws uncertain, and that people would then live in society “without exactly knowing the nature of their obligations.” The judges must be “no more than the mouth that pronounces the words of the law, mere passive beings, incapable of moderating either its force or rigour.” This mechanical view of the proper role of the judges can be found in the writings of Lilburne and Harrington during the Civil War in England, and it is perhaps from the latter that Montesquieu obtained this notion. Its influence in the nineteenth century and in the early part of the twentieth, until the rise of the “sociological” school of jurisprudence, was a formidable one indeed. Second, he emphasizes the importance of judicial procedures as a protection for the individual. The speedy decision of cases may be cheaper and easier, but the set forms of justice with all their expense and delay, even the very dangers of the judicial procedure, are “the price that each subject pays for his liberty.” In despotic governments speed is the only consideration, but in moderate governments long inquiries and many formalities are necessary before a man is stripped of his honour or property, or of his life. This insistence upon “due process,” a phrase Montesquieu does not use but which again was current in seventeenth-century England, is of the essence of the doctrine of constitutionalism, in the development of which his thought forms such an important step.

By 1748, therefore, he had formulated the tripartite division of government functions in a recognizably modern form. A good deal of change still had to take place in the ensuing two hundred years in the exact connotation of these concepts, but basically the pattern was now set. To legislate is to make the law; to execute is to put it into effect; the judicial power is the announcing of what the law is by the settlement of disputes. These functions exhaust all the “powers” of government, and they can be clearly differentiated from each other. Every government act can be put into one or other of these categories. He also established the idea of three branches of government—executive, legislature, and judiciary. So much for the analytical separation of agencies and functions. But to demonstrate that Montesquieu had a “theory of the separation of powers” in one sense or another we must go further. We must show that he maintained that each function should be exercised by the appropriate agency of government, and that he furthermore believed that the personnel of the three branches should not coincide. It will become quite clear at a later stage that he did not maintain the pure doctrine of the separation of powers, for he combined with it the ideas of mixed government and checks and balances; however, that he did advocate that each agency should exercise, in the main, only its own functions, is also perfectly clear. He was quite explicit here:

When the legislative and executive powers are united in the same person, or in the same body of magistrates, there can be no liberty. . . . Again, there is no liberty, if the judiciary power be not separated from the legislative and executive. Were it joined with the legislative, the life and liberty of the subject would be exposed to arbitrary control; for the judge would then be the legislator. Were it joined to the executive power, the judge might behave with violence and oppression. There would be an end to everything, were the same man, or the same body, whether of the nobles or of the people, to exercise those three powers, that of enacting laws, that of executing the public resolutions, and of trying the causes of individuals.

The representative body ought not to exercise the executive function, because it is not suited to it. The legislature ought not to be able to arraign the person entrusted with the executive power, for this would turn the legislature into a body with arbitrary power. One cannot ignore the clear meaning of these words. Montesquieu believed that the various functions of government should be entrusted to distinct agencies of government, which would be largely independent of each other in the exercise of these functions. The problem of the extent to which each of these agencies should be able to control the others will be considered later.

We have seen that even given the attribution of distinct functions to separate agencies there still arises the problem of personnel. Should the personnel of the agencies be quite distinct, or should a degree of overlapping be allowed, or does it not matter at all? Montesquieu is less clear on this point than on the other elements, although there are strong indications of his line of thought. When writing of monarchy he does not envisage a separation of legislative and executive functions in practice, so the question of personnel does not arise; however, he does express shock at the idea that royal ministers should also sit as judges. There is, he says, a sort of “contradiction” between the prince’s council and the courts of judicature. The former requires a certain passion in the conduct of its affairs by a few men who identify themselves with its business, whereas the courts demand a certain “sang-froid” and a measure of indifference on the part of the judges.54 Once again we have this emphasis upon the impartiality of the judiciary. In his discussion of the judiciary in Book XI, he is less explicit, but the nature of the selection of the judges, or rather juries, is such that the problem of whether or not they should simultaneously be legislators, or in the service of the king, hardly seems to arise. These ad hoc juries are so impermanent that the problem of the overlapping of membership with the more professional and permanent members of the other branches does not arise.

The problem of the separation of the personnel of the legislative and executive branches in the constitution of liberty was also very obliquely dealt with by Montesquieu. He paid little attention to the servants of the king, other than ministers, and so there was no great scope for discussions of the extent to which they should be allowed to be legislators as well. He did, however, echo the English writers who condemn corruption of legislators—the English State will perish “when the legislative power shall be more corrupt than the executive.” However, one very important change from the contemporary English theory that he made, concerning the composition of the executive and legislative branches, must be noted here. The English writers saw the legislative power as held jointly by King, Lords, and Commons, even though the King’s role might be seen as only a negative one. This sharing of the legislative power was the foundation of their theory of the balanced constitution, and it continued to be so even after Montesquieu’s work had received general acclaim as a eulogy of the English Constitution. They therefore wrote of “the King-in-Parliament.” Montesquieu, however, looked at the problem in a slightly different way. He wrote of the “legislative body” as composed of “two parts,” with the executive separated from them. He did give to the executive a veto power, which he described as having a share in legislation (prendre part à la législation), but the emphasis of his usage is important. Whereas the English writers saw the King as an essential part of the legislative branch itself, he saw the executive as a separate branch which has a part to play in the exercise of the legislative function. The importance of this difference of emphasis becomes clear when we compare the differing approaches of the English and American writers at the end of the eighteenth century. This would suggest, then, that Montesquieu saw the King, “the person entrusted with the executive power,” as outside the legislature; if, therefore, the King really makes the decisions, and provided that he cannot corrupt the legislature, it does not matter whether or not his subordinates are members of the legislature or not. This view is supported by the fact that Montesquieu argued that if the executive power is not in the hands of a monarch, but is committed “to a certain number of persons selected from the legislative body, there would be an end then of liberty; by reason the two powers would be united, as the same persons would sometimes possess, and would be always able to possess, a share in both.” This would seem to be a reference to the ministerial system in England, and to the view that if the monarch were no longer head of the executive, or perhaps became a mere figurehead, with real power in the hands of his ministers, then the concentration of power would be a genuine danger. Those who accuse Montesquieu of being wholly unaware of the contemporary development of cabinet government in England seem to overlook this passage. It should be borne in mind that when he wrote, the King still exercised considerable power—Montesquieu looked forward to a period when this would, perhaps, no longer be the case.

He did not, therefore, work out in detail the problem of the overlapping of the personnel of the agencies of government, and he certainly did not issue a general prohibition. It is strange that he made no direct reference to the problem of place-bills, which had been so important in England. But the spirit of what he had to say seems clear enough; whenever it is a question of the exercise of real power the agencies of government should not come under the control of a single person or group of persons. “When the legislative and executive powers are united in the same person, or in the same body of magistrates, there can be no liberty.” Detailed analysis of Montesquieu’s words should not be allowed to blind us to what he had to say.

Having shown that all the elements of the pure doctrine of the separation of powers are to be found, if not always clearly worked out, in Montesquieu’s thought, can we simply label him as a protagonist of the pure doctrine? Clearly not, for he went further, and added to these ideas the further dimension of a theory of checks and balances between the legislative and executive powers, drawn largely from the theory of mixed government. He did not rely upon a concept of negative checks to the exercise of power, checks dependent upon the mere existence of potentially antagonistic agencies, charged with different functions of government—again he went further, and advocated positive checks by placing powers of control over the other branches in the hands of each of them. Perhaps the first important point to note about his theory of checks and balances is that in Book XI it does not involve the judiciary or “the power of judging” at all. The judiciary is not given any power over the other branches. Equally, its independence is absolute, for it is not subject to control by the other branches, except that the legislature can be a supreme court of appeal in order to mitigate the sentence of the law. The courts, in other words, being merely the mouthpiece of the law, being en quelque façon nulle, and not representing any social force in the State, are not seen as a check, nor is it necessary to check them. The difference between this view of judicial power and that of Chief Justice Marshall in Marbury v. Madison, fifty-five years later, is of great interest although it is true that Montesquieu elsewhere saw the French parlements with their rights of remonstrance as checks to the legislative power.

The relationships between the executive and legislative branches, however, exhibit clearly the characteristics of the idea of checks and balances that we saw in the English theory of the balanced constitution. The executive officer ought to have a share in the legislative power by a veto over legislation, but he ought not to have the power to enter positively into the making of legislation. The executive should have the power of calling and fixing the duration of meetings of the legislative body. In this way the executive branch will be able to prevent the encroachments of the legislature on its authority, thus ensuring that the legislature will not become despotic. The legislature should not, however, have the right to stay (arrêter) the executive, but it should have the power to examine the manner in which its laws have been executed. Whatever the results of this examination, the legislature should not be able to judge the person, or the conduct of the person, who executes the law. However, the counsellors upon whose advice unwise policies are adopted may be punished, and for this purpose the power of impeachment must lie in the legislature, with the Lower House accusing, and the Upper House judging. “Here, then, is the fundamental constitution of the government we are treating of. The legislative body being composed of two parts, they check one another by the mutual privilege of rejecting. They are both restrained by the executive power, as the executive is by the legislative.” Montesquieu, though he had great faith in the power of constitutions to mould the public character of a State, was nevertheless sufficiently aware of sociological necessity to see the importance of having the essential parts of the State as representative of different interests in society; and so he adapted the theory of mixed government to the underpinning of a system of divided powers, in order that the varying “passions and interests” of the different classes of society should ensure that no one man or group of men gained arbitrary power. This does not mean that he threw overboard the notion of the separation of powers. It still remained as the foundation of the constitution of liberty, as he frequently reasserted, but certain quite specific and limited powers were attributed to the executive to enable it to control the legislature, and to the legislature to control the subordinate members of the executive. These control mechanisms did not constitute a “fusion” of powers; they were links between the branches of government, each restricted to the exercise of its appropriate function. The practical problems of these controls, the extent to which they embodied an opportunity for co-ordination, or alternatively for deadlock, between the branches, was not yet clearly perceived, although Montesquieu at a later stage devoted some time to a discussion of the nature of party politics in England, with its division of the legislative and executive powers.55 Thus Montesquieu clearly did see a broad separation of functions among distinct agencies of government, with a separation of personnel, to which was added the need for a set of positive checks to the exercise of power by each of the two major, permanent, agencies of government to prevent them from abusing the power entrusted to them. The ideas of independence and interdependence which Bolingbroke developed are useful here for the understanding of this system. Without a high degree of independent power in the hands of each branch they cannot be said to be interdependent, for this requires that neither shall be subordinate to the other. At the same time a degree of interdependence does not destroy the essential independence of the branches.

Montesquieu was aware of the problem of ensuring that a system of government so nicely balanced should not result in complete deadlock, that the three bodies, King, Lords, and Commons, by being poised in opposition to each other should not produce merely a state of “repose or inaction.” But he dismissed the problem by arguing that in the nature of things they are forced to move (par le mouvement nécessaire des choses), and forced to move in concert. The question of whether he saw the State as an organic unity in which the articulated parts formed a single unit exercising the sovereign power, or whether he destroyed the unity of sovereignty by dividing it up into parts which were to be distributed among quite distinct, autonomous bodies, related to each other in a mechanistic fashion only, is probably impossible to answer, because it is doubtful if he ever formulated the problem in either of these ways.56 He seems to have a unitary view of the supreme power when he is discussing his three forms of State in the initial books of De l’Esprit des Loix, but there is little clue to his attitude in Book XI, Chapter 6. On the question of legislative supremacy he seems, though less explicitly, to hold much the same position that we attributed above to John Locke. The legislative function is logically prior to the rest in the sense that the executive and judicial functions are concerned with putting the law into effect; but the legislative branch must be limited in its power to interfere with the acts of the executive branch, otherwise the former will be able to wield arbitrary power. Montesquieu does not, however, emphasize the supremacy of the law, or of the legislative function, to anything like the extent Locke had done, and as a consequence there seems to be a good deal more disagreement between them on this point than was probably the case.

What then did Montesquieu add to seventeenth- and early-eighteenth-century English thought on the separation of powers? Clearly his view of the functions of government was much closer to modern usage than his predecessors’—he was one of the first writers to use “executive” in a recognizably modern sense in juxtaposition with the legislative and judicial functions. His emphasis upon the judicial function and upon the equality of this function with the other functions of government, though (as we have seen) by no means altogether new, was nevertheless of great importance. The judiciary had a position of independence in his thought greater than that of earlier English writers, and greater than it was in practice at that time in England. Although he used the idea of mixed government he did not allow it to dominate his thought, as had the writers on the balanced constitution in England; consequently he articulated the elements of the constitution in a different way, and a clearer view of the separation of legislative and executive branches was now possible. He had gone a long way, in fact, towards the transformation of the theory of mixed government from its position as a doctrine in its own right into a set of checks and balances in a system of agencies separated on a functional basis. Perhaps the most significant difference between Bolingbroke and Montesquieu is that the latter placed the King outside the legislature. In some ways, then, Montesquieu moved back towards the emphasis that was placed during the Protectorate upon separate and distinct powers; he was certainly closer to the pure doctrine than his English contemporaries, but he did not go all the way. He had a more realistic, more articulated system, with an amalgam of seventeenth- and eighteenth-century ideas woven into a new fabric. Sometimes it is difficult to know whether the changes he introduced into the stream of political thought on constitutionalism were wholly intentional, or whether they resulted rather from his method of writing. We shall never know—but it does not matter. The very defects of his style gave him an influence which a more precise and less interesting thinker would never have achieved, but more important than this is the fact that by changing the emphasis that English writers of the preceding half century had placed upon legislative supremacy and the mixed constitution, he paved the way for the doctrine of the separation of powers to emerge again as an autonomous theory of government. This theory was to develop in very different ways in Britain, in America, and on the continent of Europe, but from this time on, the doctrine of the separation of powers was no longer an English theory; it had become a universal criterion of a constitutional government.

[1. ]On the English origin of Montesquieu’s ideas, see J. Dedieu, Montesquieu et la tradition politique anglaise en France, Paris, 1902.

[2. ]The standard edition of De l’Esprit des Loix is by J. Brette de la Gressaye, Paris, 1950, 4 vols. Quotations are from the translation by Thomas Nugent, ed. by F. Neumann, New York, 1949.

[3. ]De l’Esprit des Loix, Book I, Ch. 3.

[4. ]L’ABC, quoted by W. Struck—Montesquieu als Politiker, Berlin, 1933, p. 4.

[5. ]See the discussion of Montesquieu’s concept of human nature in W. Stark, Montesquieu: Pioneer of the Sociology of Knowledge, London, 1960, Ch. IV.

[6. ]De l’Esprit des Loix, XIX, 27.

[7. ]Ibid., XI, 4.

[8. ]Ibid., I, 3.

[9. ]Ibid., II, 1.

[10. ]Ibid., II, 3.

[11. ]Ibid., VIII, 2.

[12. ]Ibid., VIII, 16.

[13. ]On Locke see Dedieu, op. cit., Ch. VI; on Bolingbroke see Robert Shackleton, “Montesquieu, Bolingbroke and the Separation of Powers,” French Studies, Vol. III, 1949.

[14. ]See Dedieu, op. cit., p. 71 for a list of French historical works on England 1689–1748, and pp. 73–74 for a list of English political works translated into French during the same period.

[15. ]Lettres sur les Anglois, Basle, 1734, p. 56.

[16. ]Shackleton, op. cit.

[17. ]See W. F. Church, Constitutional Thought in Sixteenth-Century France, Harvard, 1941, esp. Ch. I.

[18. ]Church, op. cit., p. 221.

[19. ]Shackleton, Montesquieu, pp. 280–1.

[20. ]See Neumann’s Introduction, pp. xxiv–xxvii.

[21. ]For a general discussion of Bodin and Montesquieu see A. Gardot, “De Bodin à Montesquieu,” in La pensée politique et constitutionnelle de Montesquieu, Paris, 1952.

[22. ]Six Bookes, II, 3, p. 204.

[23. ]De l’Esprit des Loix, V, 14.

[24. ]Ibid., II, 4.

[25. ]Shackleton, in Montesquieu, p. 279, describes how the emphasis upon the subordinate character of the intermediary powers was a later insertion in the text by Montesquieu, perhaps as a precaution against royal displeasure. However, this insertion would seem to be in the general spirit of Montesquieu’s view of monarchy.

[26. ]De l’Esprit des Loix, VI, 5.

[27. ]Ibid., VI, 6.

[28. ]Ibid., VI, 2.

[29. ]Ibid., VI, 3.

[30. ]Ibid., II, 4, and V, 10.

[31. ]Ibid., III, 10.

[32. ]Thus K. von Raumer argues that Montesquieu saw, even in the France of Louis XV, the idea of freedom embodied in Europe, as opposed to the slavery of Asia. Although this freedom was threatened it was still a reality, such that France was still a moderate monarchy, not a tyranny. (“Absoluter Staat, korporative Libertät; persönliche Freiheit,” Historische Zeitschrift, Vol. 183, Munich, 1957, p. 59.)

[33. ]Ibid., VIII, 21. W. Struck argues that Montesquieu’s principles of the three forms of government are by definition incapable of being blended into a mixed form. Montesquieu als Politiker, Historische Studien, 228, Berlin, 1933, pp. 68–69.

[34. ]All further quotations in this chapter are from Book XI, Ch. 6 of De l’Esprit des Loix unless otherwise noted.

[35. ]Ibid., XI, 12.

[36. ]De l’Esprit des Loix, VI, 3.

[37. ]Six Bookes, II, 1, p. 183.

[38. ]Ibid., II, 12, pp. 199–200; and II, 7, pp. 249–50.

[39. ]De l’Esprit des Loix, V, 19.

[40. ]Ibid., XIX, 27. In this reference and the preceding one Montesquieu does not refer to England by name, but it is generally accepted that it was to England that he was referring.

[41. ]B. Mirkine-Guetzévitch, in La pensée politique et constitutionnelle de Montesquieu, p. 14. Mirkine-Guetzévitch asserts that none of Montesquieu’s contemporaries thought that he was writing of the reality of English political life.

[42. ]Ibid.

[43. ]Franz Neumann’s introduction to The Spirit of the Laws, New York, 1949, pp. liv–lv.

[44. ]“Il n’y a point encore de liberté si la puissance de juger n’est pas séparée de la puissance législative et de l’exécutrice.”

[45. ]See the discussion by Charles Eisenmann, in La pensée politique et constitutionnelle de Montesquieu, pp. 135 ff.

[46. ]M. Barckhausen, Montesquieu, ses Idées et ses Oeuvres, Paris, 1907, p. 95.

[47. ]C. Eisenmann, L’Esprit des Lois et la séparation des pouvoirs in Mélanges R. Carré de Malberg, Paris, 1933, pp. 166 ff.

[48. ]Stark, op. cit., p. 21.

[49. ]Montesquieu always uses “la puissance de juger,” not “le pouvoir judiciaire.

[50. ]He justifies this stability in the legislative and executive powers by declaring that “they are not exercised on any private subject.”

[51. ]Franz Neumann, op. cit., p. lviii.

[52. ]De l’Esprit des Loix, VI, 3.

[53. ]Ibid.

[54. ]De l’Esprit des Loix, VI, 6.

[55. ]XIX, 27.

[56. ]Stark, op. cit., Ch. I, discusses this problem, arguing that Montesquieu had a semi-organic rather than a mechanistic concept of the State.