aristocracy, and democracy. He did so, however, in a very formal way, and the medieval references to the theory seem to have little depth or reality until in England the institutional and political developments provided a factual basis for the theory to work upon.61 With the development of representative institutions in England, however, the idea of the best system of government as a combination in which King, Lords, and Commons shared the power of government developed, until the theory of mixed government became, in seventeenth-century England, the dominant political theory of the age. In the late fifteenth century Sir John Fortescue saw three kinds of government: dominium regale, absolute monarchy, dominium politicum, republican government, and dominium politicum et regale, a mixed form, which was the pattern of English government.62 Bishop Poynet, in 1556, asserted that men had long judged “a mixte state” to be the best of all, and that where it had been established it had been the most stable form of government.63 Sir Thomas Smith, a few years later, saw the English system as a threefold mixture. The Commonwealth of England is “governed, administered, and manured by three sortes of persons”—the Prince, the gentlemen, and the yeomanry.64 However, neither Fortescue, Poynet, nor Smith was fired by the desire to limit the power of the monarch to the exercise of only one specific function of government. For it is this demand, the requirement that the monarch be limited to the execution of the law, which is the beginning of the doctrine of the separation of powers, and at the same time the beginning of the end for the doctrine of mixed government. At the end of the sixteenth century it was in France rather than in England that this demand seemed to be on the point of being formulated, for in France the extreme difficulties of the Huguenots were such as to stimulate such an approach. François Hotman, writing in 1573, insisted that the French system had historically been a mixed government, that the power of making laws had, till a century earlier, been entrusted to a “public annual council of the nation,” later called the three estates, and he seemed to be on the verge of demanding that the King be limited to the “administration of the Kingdom.”65 The authors of the Vindiciae contra Tyrannos were also striving towards a similar position.66
In mid-seventeenth-century England the theory of mixed government became a commonplace of political writers, until, indeed, in 1648 Sir Robert Filmer, himself the strongest opponent of the theory, could write: “There is scarce the meanest man of the multitude but can now in these daies tell us that the government of the Kingdome of England is a Limited and Mixed Monarchy.”67 Charles I made an acknowledgment of the doctrine in his reply to the Nineteen Propositions of 1642. It was at the height of the theory’s popularity that the attempt to make it fit the circumstances after 1641 brought forth a new and different theory, the separation of powers. The theory of mixed government was from the earliest times intended to provide a check to the exercise of arbitrary power by the balancing of the “powers of government” in a constitution. But before the intense political activity of the mid seventeenth century, the exact articulation of the elements of a system of mixed government had not been explored. The outbreak of open hostilities between King and Parliament prompted attempts by the protagonists of the theory to define the relative functions of the elements of the government. The failure in the sphere of practical politics of the attempt to find a workable compromise resulted in the creation of conditions in which mixed government seemed irrelevant, and the way was clear for the new doctrine.
The impact upon constitutional thought of the dispute between King and Parliament can be seen in the way in which two major theories of government, which were to act and react upon each other for the next two centuries, were formulated in the 1640’s and rapidly developed into impressive schools of thought. The theory of mixed government, which earlier had been rather vague and lacking in articulation, was refashioned in Charles I’s Answer to the Nineteen Propositions into the basis of the later theory of the balanced constitution. Published in 1642, some months before hostilities actually started, the Answer presented a combination of mixed government and a division of the tasks of government among its parts in such a way that they might each check the power of the others.68 At the same time Parliament’s supporters were evolving a theory of government that placed less stress upon mixed government, and which depended heavily upon an abstract formulation of the powers of government and the allocation of these functions, in fact the basis of the theory of the separation of powers.
The starting point in a discussion of the “transition” from the theory of mixed government to the doctrine of the separation of powers may begin with the work of Charles Herle, a supporter of the Parliamentary cause. Writing in 1642, Herle made quite explicit the scattered suggestions in the earlier literature that the three elements of the mixed constitution, King, Lords, and Commons, had a co-ordinate status.69 But did this mean that all three were co-ordinate in the exercise of all the functions of government? Dr. H. Ferne, Herle’s opponent, asked if Herle was asserting that the two Houses were co-ordinate in both the enacting and the execution of law.70 In reply Herle took the position that whilst the two Houses had a status superior to the King’s in the exercise of the legislative power, and the representative character of the Commons gave it the “largest share” of this power, it was above all in the execution of the laws that the Houses had a status co-ordinate with the King’s. Of what use, Herle asked, is the co-ordinate status of the Houses in the making of law, if they have not the power to ensure the execution of the laws?71 Herle, of course, was not proposing a division of functions into distinct hands; quite the reverse. He was using the ancient idea of a fusion of the functions of government, rather than their separation, in order to justify the action of Parliament in taking up arms against the King. However, the emphasis he placed upon the co-ordinate status of King, Lords, and Commons, was to be reflected in later writing, where the problem was to ensure that the person entrusted with the executive power was not merely a subordinate official but had a position and autonomy of his own. He was also one of the first to raise the basic problem of any theory which divides functions among agencies: if the legislature were restricted solely to passing legislation, what guarantee would it have that its commands would be properly carried out?
In 1643 one of the most competent of Parliament’s supporters, Philip Hunton, undertook in his Treatise of Monarchy to clarify the theory of mixed government and the relationships between the parts of the mixed State. Hunton was the most sophisticated and systematic of the supporters of mixed government in this period, working out in detail its differing categories, although it should be mentioned that he started from a belief in the indivisibility of the “power of magistracie.”72 Hunton took a rather different line from Herle’s, a line which led him much closer to a theory of functionally divided agencies of government. First, he established the difference between “mixed government” and a “mixed monarchy.” Governments can be simple or mixed, limited or absolute. Mixed governments are always limited governments, although the reverse is not true. The general term “a mixed State” is, however, only appropriate when “the highest command in a state by the first constitution of it is equally seated” in all three of the elements of the government.73 This, then, is broadly what Herle had been describing. However, a more stable State is likely if one of the three elements is “predominant,” and where this is so the predominant element “gives the denomination to the whole.” Thus England is a “mixed monarchy.”74 In such a mixed monarchy the sovereign power must be originally in all three elements, for this is the reason for the mixture, that “they might confine each other from exhorbitance.”75 Nevertheless, if it is to be a stable mixed monarchy, then there cannot be full equality in the three estates. “A power then must be sought wherewith the Monarch must be invested, which is not so great as to destroy the mixture; nor so titular as to destroy the Monarchy.”76
Hunton’s answer to this problem was to suggest a number of powers which, vested in the King, would give him this position of limited dominance. The first of these, and the most important, was the executive power. The “power of magistracie,” said Hunton, has two degrees; it is “Nomotheticall or Architectonicall and Gubernative or Executive.”77 The King can be made “head and fountain of the power which governs and executes the established laws, so that both the other States … be his sworn subjects, and owe obedience to his commands, which are according to established lawes.”78 The King is, then, to be the executive, but what