The ancient Greco-Roman idea of the “mixed constitution” is usually taken to be the ancestor of modern (post 18th-century) constitutional ideas about “checks and balances” and the “division of powers.” This is fine as far as it goes; the early modern writers who first proposed and defended these latter ideas in a systematic way – people like Harrington, Locke, and Montesquieu, for example – seem to have been influenced to some degree by Greek and Roman theories of the mixed constitution. They used these ideas as one of the lenses through which they interpreted British constitutional practice of the 17th and 18th centuries; and there is certainly a sort of family resemblance between the ancient idea about the need for “mixture” in a constitution and the modern idea that a constitution should implement some checks on state power through the functional division of authority among different “branches” of the government.
However, as many people have noted, ancient ideas about the mixed constitution are in many ways quite different from modern ideas about the need for a functional division of authority to prevent abuses of state power. Even the guiding metaphors are different: “mixture” and “separation” denote contrary ideas. But perhaps more importantly, it strikes me that ideas about the mixed constitution played a role in ancient Greco-Roman political discourse that is very different from the role that ideas about “checks and balances” came to play in modern political discourse, and that is in fact surprisingly similar to the role ideas about the “mixed economy” – an economy that incorporates both market mechanisms and government intervention – play in contemporary political thought. I don’t mean this as a claim about intellectual history: ideas about the “mixed economy” today clearly owe nothing to ancient ideas about the mixed constitution. I mean it as a claim about the conceptual place of ideas within particular discourses or debates. Let me try to explain.
As I argue in much pedantic detail in a piece I published last year somewhat misleadingly entitled “Cicero and the Stability of States” (History of Political Thought 32(3): 397-423 [gated, ungated] – the first half is a survey of ideas about the mixed constitution in Plato, Aristotle, and Polybius), ancient ideas about the mixed constitution have two strands.
On the one hand, there is a concern with domination by powerful people and groups. Here the idea of the mixed constitution serves as a model of the “constraints” that should be imposed on the powerful to prevent tyranny, and in this sense it plays a very similar role to ideas of “checks and balances.” However, whereas modern discussions about the separation of powers tend to emphasize the need for a functional division of the tasks of government (into legislative, executive, and judicial activities, for example) to prevent abuses of state power, ancient discussions of the mixed constitution tend instead to emphasize a social division of power among significant social groups to prevent its monopolization (a group “becoming” the state, so to speak). The “simple” or “unmixed” regimes are precisely those regimes where one social group – the rich, the poor, military leaders – monopolizes power (for good or ill; the unmixed regimes are not always considered bad, but they are always considered fragile for a variety of reasons); by contrast, the “mixed” regimes are precisely those where power is “shared,” or, metaphorically, these are the regimes which "mix" the monopolistic regimes so that no social group has uncontested dominance over the others.
To put the point very roughly, I suspect the modern emphasis on separating power goes hand in hand with an emerging consciousness of “the state” as a distinct unified institutional actor that can develop interests that are independent of those of other significant social groups (including dominant groups), and hence is concerned with the institutional mechanisms that can limit its ability to act in dominating ways; ancient political thought, by contrast, has no such consciousness of a “state” as distinct from the social groups that exercise political power (most Ancient Greco-Roman societies had nothing like a state in the Weberian sense of the word anyway), and hence is more concerned with the compromises that various groups need to make to share power stably in ways that are beneficial to all. This is only an imprecise sketch of a complex history, of course. After all, early modern liberal political thought was often also concerned with the problems posed by the domination of one social group over another; 19th century debates about suffrage are full of fears about what would happen if the poor were allowed to directly elect representatives and hence dominate the state, for example. And 17th and 18th century notions of “estate representation” do fit in quite naturally with ancient ideas about mixed constitutions. Yet I am tempted to speculate in a vaguely Marxist way that ancient Greco-Roman political thought was more attuned to the permanent class conflicts of agrarian societies than early modern liberal thought, perhaps because the latter in part grew out of reflections on the management of confessional or sectarian conflicts in which the state was never merely a class agent, unlike the former.
At any rate, this concern with “sharing” power among significant social groups leads to a second strand of thought about political “mixture.” Here the idea of the mixed constitution serves as a model of the compromises that are possible and necessary between groups whose conceptions of justice – their conceptions of the appropriate distribution of the “benefits and burdens” in the community, their ideas about the appropriate level of hierarchy and equality in the organization of society, and so on – differ systematically according to their positions in society. For example, both Plato and Aristotle (and to a lesser degree other extant writers) suggest that the poor and the rich develop conceptions of justice that have a certain “bias” towards their own structural position: while the poor or the people tend to develop a conception of justice that emphasizes their equality as citizens, and hence the need for an equal distribution of power and authority in the community (expressed most radically in the lotteries of Athens), the rich or the elite tend to develop a conception of justice that emphasizes their inequality – their distinctiveness – and hence the need for an unequal distribution of power and authority (expressed in the demand for closed oligarchies and in justifications that claim the right to rule for those who contribute the most to the community, or those who are wisest, or have the most military virtue). Conflict between major social groups is not simply a clash of naked self-interest (at least not always), but rather appears as a contest between rival moralized conceptions of hierarchy, equality, and fair distribution.
For these Greek (and later Roman) writers, the key theoretical problem thus turns out to be how to bridge these divergent conceptions of justice for the sake of political stability while also promoting as far as possible various other important goods – freedom, independence, the effectiveness of the community as a fighting force, social solidarity, prudent decisionmaking, etc. How can political power be shared so that these contrasting conceptions of justice can all find some place in the community without monopolizing the whole, while maintaining a viable, even flourishing society in other respects?
This problem is complicated both by material factors (extreme inequality makes it difficult to bridge the conceptions of justice of significant social groups, in the view of most of the extant Greek writers who talk about this problem) and by the fact that these group-relative conceptions of justice, however faulty, cannot be fully “educated away.” That is, whatever the truth of the matter about justice is (and Greek and Roman thinkers thought this was an answerable question) it is simply not possible to consistently convince people in structurally different positions that their conceptions of justice are incorrect. (At best, education can soften the edges of those differing conceptions of justice, but not transform them consistently). The “mixed constitution” is then an attempt to describe how one might give all these different conceptions of justice – or different ideas about what is valuable, or what gives people title to rule – some place within the polity despite the fact that they are partially incorrect (because one-sided) and hence in some ways damaging to the community, and despite the fact that they cannot be "corrected," while not wholly sacrificing other important values. In Plato, for example, the test of a well-organized mixed constitution is that it balances the characteristic values associated with “democracy” (where the poor or the many are dominant) and “monarchy” (a synecdoche for all regimes where small elites are dominant) so as to promote philia (social solidarity), eleutheria (freedom and political independence) and phronesis (prudent decisionmaking). Let me quote myself:
The Athenian Stranger [the main speaker in Plato’s Laws] suggests that a constitution can achieve these three objectives by “mixing” in the right proportion the values traditionally associated with monarchy, especially Persia, and the values traditionally associated with democracy, especially Athens (693d). “Monarchical” values emphasize subordination and status hierarchies, and thus enhance the coordination of action necessary to effective military power, i.e., the kind of power that ensures eleutheria as political independence (694a). But if they are over-emphasized, they disrupt both the solidarity and affection (philia) between rulers and ruled and the ability of information and insight to flow to the rulers (phronesis; 694a-b), increasing the city’s vulnerability to external forces and diminishing the ability of rulers to actually rule for the common good (697d-698a). By contrast, “democratic” values emphasize personal autonomy and equality, and thus enhance the solidarity and affection between rulers and ruled as well as the flow of information throughout the city, which makes the city able to defend itself intelligently at least so long as it can coordinate its actions through its laws and rulers even against vastly superior forces (cf. 698b-699d). But if they are over-emphasized, the city loses both its ability to recognize and defer to actual expertise (and hence loses intelligence; cf. 701a) and the ability to coordinate properly that submission to laws and rulers provide. It thus disintegrates into “every man for himself” (cf. 699c-d), again making it vulnerable to external forces.
Properly constructed institutions will ensure that the citizens will be properly submissive to the laws and the rulers (indeed, that they will “fear” and “revere” the laws and the rulers, cf. 698b), but will also grant enough personal autonomy and ensure enough status equality to ensure that phronesis flows through the city and rulers and ruled share enough affection for each other. Such a constitution will “weave together” the “mother constitutions” of monarchy and democracy (693d) in the sense that it will induce a measured combination of their characteristic values capable of simultaneously ensuring solidarity and affection between rulers and ruled, intelligence in the actions of the city, and the preservation of its political independence. (moi, pp. 403-404)
Though “liberalism” as such did not exist in the Ancient Greco-Roman world, the idea of the mixed constitution thus seems to me to be designed to deal with problems similar to those that have motivated much modern liberal thought: how to deal with intractable conflicts of value (about justice, in this case) when no significant social group can be assumed to have a monopoly on the truth (the philosopher does not count as a social group, even if she does have the truth about justice) in a relatively peaceful way. But ancient mixed constitution thinking (at least the mostly Greek variant of it before Cicero that has come down to us), unlike classical liberalism, tended to see these problems in the context of deep-seated, ineradicable distributional conflicts; and as such, it seems to me, it played a role in political thought similar to the role the idea of a “mixed economy” plays today.
Modern economic debates about the role of the state in the economy are obviously never merely technical debates; they usually invoke, either implicitly or explicitly, different conceptions of justice and fairness, and different answers to the question about the kinds of power that partisans of these conceptions of justice and fairness ought to have in society. (Consider: "taxation is theft" vs. "you didn't build that"). They are debates about what is the right distribution of burdens and benefits in society, and draw on deep-seated intuitions about desert, property, and the like that appear to vary among distinct social groups. The idea of a mixed economy then serves as a model – varying in detail depending on its particular proponent, of course – of the appropriate distribution of social power among partisans of different conceptions of distributive justice, including both a description of the kinds of constraints that should be imposed on powerful social groups (e.g., how democratic states should constrain markets and vice-versa) and a description of the kinds of compromises that partisans of particular ideas of fairness or justice must make while still promoting efficiency (the modern equivalent of the Platonic “prudent decisionmaking” or phronesis), common identity (the modern equivalent of the Platonic philia), and personal autonomy (the modern equivalent of eleutheria).
Proponents of a mixed economy of course disagree about the specific institutions of that would instantiate it properly, just as Plato, Aristotle, Polybius, and Cicero had different views about proper mixture in a constitution. My point is more about how the abstract model of the mixed economy seems to serve as a reference point for attempting to find pragmatic compromises among social groups with ineradicably different views concerning distributive justice and enduring, if unbalanced, forms of social power (numbers vs. economic power, for example) even if we think that some of these views are correct (or more correct than others). We might say that like the mixed constitution in antiquity, the mixed economy today serves as a standard description of the second best.
Update 7 August: fixed some oddities of grammar and missing words.
Update 7 August: fixed some oddities of grammar and missing words.