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