Polybius’ theory was the last of the Greek constitutional theories known to us. The Greek theories show how constitutional mixing became an analytical tool to identify the most effective compromises for preventing civic strife and ensuring the survival of a city-state. Each one was developed consciously on the basis of empirical evidence from actual governments that displayed superior stability or civic excellence. As time went on, the scope of the examples was extended. Thucydides looked only at three Athenian constitutions and explained the best as a mixture. Plato, having witnessed Athens’ defeat, expanded his range of comparative examples to include Athens’ rivals, the Persians and the Dorian Greeks, as well as Athens’ governments in the more distant past. Aristotle made an effort to include all Greek cities over their entire histories, as well as Carthage. Two centuries later Polybius added Rome to his repertory of effective constitutions that could most aptly be analyzed as mixed constitutions.
From Plato onward, the standard basis for judging the effectiveness and quality of a model of political compromise was its conformity to normal human psychology. For service in the real world, and not only in an imaginary utopia, this was essential. Though all the models recognized the tendency of security, luxury, and power to corrupt rulers and the complementary tendency of their exploited subjects to feel hostile to the point of rebellion, there was no agreement on what kind of compromise would promote self-control and moderation in rulers. Three strategies for implementing compromise and reconciling opposed factions appear in the four mixed constitutions that are known to us:
1 Privileging the economic mean among citizens, as Thucydides noted in the Athenian constitution of the 5,000 or as Aristotle advocated in respect to his ‘‘middle’’ constitution.
Splitting the authority and honors of rule fairly among the contenders, as Aristotle proposed for his ‘‘polity.’’
3
Balancing or linking opposing organs of government or regimes so they cannot succeed without cooperating with the opposition, as Plato found in the Spartan constitution and Polybius found in both Sparta and Rome.
The choice of strategy depended on the agents entering into the compromise. Determining the relevant agents was crucial, for unless the source of the conflict was correctly identified, the opposing components could not be reconciled. For Thucydides and Aristotle it was the socioeconomic classes of the city, for Plato the various organs of government, the individuals and bodies assigned to make decisions in the city-state. For Polybius it was the regimes operating in and through the state, the sociopolitical segments of the population that constitute sources of authority in the citizen body and the individuals or groups who mediate that authority in the governing process.
These diverse attempts to theorize mixed constitutions were not ivory tower exercises, but serious attempts to bring rationality, the lessons of history, and the results of contemporary social science to bear on the most urgent political problems of ancient times: how to achieve civic cohesion and benevolent governance for the common good. There is no evidence that any of them were successful in furthering these goals in their own states. In fact, the concept of compromise through a ‘‘mixed constitution’’ was eventually forgotten. It had not been a central independent concept in Plato or Aristotle, but developed incidentally in their quest for the best constitution. When its strategic importance was recognized, it was by practical statesmen, Polybius in Greece and later Cicero in Rome; but the books in which they defended the idea were eventually lost. The relevant portion of Polybius’ History survived only in a Byzantine collection of excerpts of the work. Cicero’s account in De republica was completely lost and not rediscovered again until the nineteenth century.
But the principles of the Greek mixed constitution were not lost; they found a warm reception in medieval and early modern Europe and stimulated reflection on contemporary politics and history and profoundly shaped medieval and early modern political thought. With the translation of his Politics into Latin in the thirteenth century, Aristotle’s theorizations came to serve as a basis for medieval political theory and for analyzing governance in England, France, and the Italian republics (Blythe 1992). In the fifteenth century the Latin translator of Plato’s Laws tendentiously claimed that the Venetians had derived their mixed constitution from Plato (Gilbert 1968: 468-70). When the Byzantine excerpts of book VI of Polybius’ History were finally translated in the sixteenth century, his formulation came to supplant the medieval Aristotelian formulation in Florence and England (Blythe 1992: 265307). In England Polybius’ conception of a mixed constitution, combining monarchic, aristocratic, and democratic elements, not only shaped the development of the British government, but was also transplanted to the British colonies in the western hemisphere, where it became the model for the American constitution. Through these modern embodiments of constitutional compromise, the ancient Greek principle of the mixed constitution continues to challenge the political agendas of nations around the globe.
World History
