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