Plato and Aristotle each left a school of followers who pursued their particular lines of thought and approach to philosophy. Dicaearchus among the Peripatetics and some of the Stoics in the third century bc wrote on the mixed constitution, but not enough survives to determine their precise contribution to the history of the idea (Blythe 1992: 24-5). The next chapter known to us was written in the second century bc by the historian Polybius (von Fritz 1975; Walbank 1972, esp. 135-50; Hahm 1995; 2000: 464-76).
By this time the political landscape in Greece had changed. After Alexander’s conquest of the Near East the Greek city-states found themselves in a world dominated by regional federations, like the Achaean and Aetolian leagues, and by the king of Macedonia, one of the powerful regional kings of the eastern Mediterranean. Late in the third century bc the Romans, having expanded their power over the western Mediterranean, began encroaching on Greece and during Polybius’ lifetime brought Greece under their control. It was the Roman conquest of Greece that prompted Polybius to write his history, crediting Rome’s mixed constitution for her success in bringing ‘‘virtually the entire world’’ under her rule (1.1.5; 6.2.3; cf. 3.1.4).
Polybius was a citizen of Megalopolis, a member of the Achaean League in the Peloponnesus. The cities of the league, though dominated by a narrow group of old wealthy families, regarded themselves as democratic (2.41-2; 4.1.5). By this they meant they had a high degree of local autonomy and were not controlled by an agent of the Macedonian monarchy. Polybius went further and regarded the league as a whole as a democracy, with the same democratic institutions as its constituent cities (2.37.7-11;2.38.5-9).In fact, he thought it fair to call the Peloponnesus a single city in every respect but one, namely, in not being surrounded by a single wall (2.37.11; 4.1.7). The sharp classical distinction between oligarchy and democracy had receded into the background by this time, and the operative distinction now was between democratic self-rule and monarchic rule by an agent of one of the powerful regional kings.
Polybius made productive use of the political theories circulating in his day to account for Rome’s success in taking control of the Mediterranean world. He constructed his theory around the standard six constitutions: the three generic types differentiated by proportion of rulers (one, few, or many), with each subdivided into an improved and an unimproved or deviant type (6.3.5-6.4.6). He defined the improved constitutions as ones based on consent of the governed, consent that is earned by a ruler’s intelligent and virtuous governance. The deviant constitutions in Polybius’ thinking are characterized by government based on force and fear or in the case of democracy on bribery and corruption (6.4.2; 6.6.10-12; 6.8.4-5; 6.9.5-7). In this he differed from Plato and Aristotle, who defined right constitutions respectively as those based on law and those aiming at the common good. He also differed from them in taking the defective or unimproved constitutions as the natural ones, from which the good constitutions were constructed by human intervention. Plato and Aristotle, with their teleological perspective, prioritized the best forms and regarded the worst as constitutions that had degenerated.
For each generic type of constitution Polybius postulated a natural historical development from its generic type to an improved version, typically followed by a decline to its deviant form. He illustrated this in the case of monarchy by a progression from the generic form of monarchy, ruled by the strongest, to an improved version, kingship, in which the people recognize the intelligence and fairness of their ruler and submit voluntarily (6.5.4-6.7.5). This improved version inevitably declines to its defective version when a ruler achieves the rule by right of birth. Feeling secure in his position, he begins to oppress and exploit his subjects, eventually triggering revolt. While the process of decline and its explanation are recognizable as preoccupations of Plato, the process leading to what Polybius called the improved or corrected version is new, though, just as in the case of Plato and Aristotle, explained in terms of the psychology of the participants. Polybius offered psychological explanations for the improvement and degeneration of each of the three generic types and for the change of one generic type into another.
In explaining these changes in sequence, Polybius portrayed a series of ostensibly successive constitutions: monarchy, kingship, tyranny, aristocracy, oligarchy, democracy, and tyranny, the last of which sets the stage for the reemergence of the first, monarchy (Polyb. 6.4.7-10; 6.5.4-6.9.10). The purpose of laying out the series of changes, he claimed, was to allow statesmen to make predictions. He called his account a ‘‘generalized conception’’ (koine epinoia) or a ‘‘generic pattern’’ (katholike emphasis, 6.5.2-3), by which he seems to have meant a universal description covering all or most cases of constitutional change (Hahm 1995: 8-37, esp. 8 n5, 12-13) and concluded that ‘‘one who has an overall view of how each naturally develops may be able to see when and how and where the growth, flowering [akme], change for the worse [metabole] and end will occur again’’ (6.4.12). Though Polybius did not claim that one can predict the timing of constitutional change, he does seem confident that one can predict which type will follow which. In the end, he summed up the process as a whole as ‘‘the cycle [anakuklosis] of constitutions, nature’s pattern of administration [physeos oikonomia] according to which the constitutional structure develops and changes and returns again to its original state’’ (6.9.10).
Polybius has often been interpreted as postulating a rigid cycle of constitutional changes. Yet as a historian he could not have failed to notice that the sequence of changes as a whole cannot be perfectly mapped onto the historical evidence (von Fritz 1975:74 -5); only a few of the changes can be found in the history of some city-state (Trompf 1979: 107-9, cf. 69-75). A closer examination of the changes, however, shows that Polybius explained all of these changes in terms of human psychology. The changes are thus as natural and predictable as human behavior. He generalized Plato’s ‘‘law’’ of the degeneration of kings into tyrants when they are born into their position by stipulating the necessary conditions for each of the constitutional changes. These conditions take the form of natural laws of social and political change (Hahm 1995: 15-37). Some of these laws or explanations of change stipulate sufficient conditions and make the change absolutely predictable, such as the deterioration of good governments into vicious forms as soon as the rulers begin holding office by hereditary succession. It was these and only these that Polybius compared to a segment of the biological cycle of birth, growth, maturity, decline, and death. The rest, including a change in the proportion of rulers, involve contingent factors and are not absolutely predictable. They are nevertheless understandable by anyone who has grasped the principles and natural laws of social psychology that Polybius had enumerated. They are thus useful for statesmen in deliberating on their city’s political policies.
In his review of constitutional change Polybius laid heavy stress on the inevitable degeneration of improved simple constitutions, because it was this degeneration that threatened constitutional stability and national strength. If Polybius wished to account for Rome’s stability and strength, he had to account for Rome’s ability to avoid degeneration and to act in full civic harmony for a common goal. Since degeneration results from a ruling power’s unqualified security, Polybius, following
Plato, contended that the only way to prevent it was to limit the ruling power’s security. He was aware that it was difficult to maintain such limitation in a simple constitution indefinitely. So he, like Plato, concluded the best constitution had to be a mixed constitution, because it created conditions that preclude unqualified security for rulers (6.3.7-8; 6.10.1-11).
Polybius distinguished two kinds of mixed constitutions: (1) those created deliberately by a lawgiver following an intentional plan, like Sparta; and (2) those that evolved naturally over a period of time, like Carthage and Rome. The Spartan constitution (politeia) was created, Polybius claimed, when the Spartan lawgiver Lycurgus
Brought together all the virtues and distinctive features of the best [simple] governments [politeumata], so that none might grow beyond its proper point and change into its corresponding evil, but rather, with the force of each being counteracted by [that of] another, none would tilt [the scale] and outweigh the other for any length of time, but the government would over time be balanced in equilibrium and would last indefinitely in accord with the principle of counteracting forces. (6.10.6-7)
Polybius adopted Plato’s idea of the organs of government curbing each other, but he understood the dynamics differently. Plato had imagined the organs of government per se as having the capability of thwarting the actions of another organ. He seemed to suppose the individuals who constituted the organs of government possess an awareness of the limited scope of their authority as well as of their need for cooperation, or at least need for the consent of another government agency. This he had assumed caused them to restrain their impulses to act solely in their own self-interest and to practice moderation in ruling. He imagined the rulers involved interacting directly with each other in the execution of their governmental functions and individually choosing self-restraint to avoid being thwarted by others.
Polybius, in contrast, imagined the interaction occurring between what he called ‘‘governments’’ (politeumata). Polybius’ mixed constitution (politeia) did not combine merely three organs of government or three governing bodies (kings, elders, and ephors), but three ‘‘governments’’ (politeumata, 6.10.6). This had the effect of combining the virtues (aretai) and distinctive properties (idiotltas) of the best governments. He identified the best simple constitutions as kingship, aristocracy, and democracy (6.3.5-6.4.5), that is, the three improved varieties of constitution. What made their combination superior to any single one of them was its stability. The constituents of Polybius’ mixed constitution were political structures (politeumata) that embodied the essential characteristics of each of the three improved simple constitutions (6.10.8-11). When he identified these as kingship (basileia) or kings ( basileis), the people (dlemos) and the elders (gerontes), he made it clear that he was talking about the relationship of a body of rulers to the city and the political institutions that mediate that relationship. Each component was a demographic element of the city-state in its capacity to participate in the government of that city-state through its particular political institutions, the dual kingship, the aristocratic body of elders, and presumably the ephors (though he did not here explicitly identify the organ of government that mediates the democratic element). Each might be called a ‘‘government’’ (politeuma) and the combination of them a mixed ‘‘constitution’’ (politeia).
As separate governments, each would follow the course of development of a simple constitution and could be expected to degenerate if its rulers held their positions securely for life (6.45.5); but combined in the mixed constitution, they did not degenerate because the three governments counteracted (antispomenes) each other by tending in opposite directions, as do the pans of a balance scale. The mechanism of the counteracting forces was psychological. The kingship was restrained from arrogance by fear of the people in their governing capacity (presumably through the ephors). The people were restrained from treating the kings with contempt because of fear of the elders, who adjudicated between the kings and the people on the basis of justice (6.10.8-10).
It is worth noting that Plato had also concentrated on the way in which the Spartan constitution prevented the degeneration of the kingship. He viewed the relationship among the three organs of government as a way to restrict the scope of the royal authority by splitting it between two kings, giving the elders the power of veto, and by authorizing the ephors to rein in both kings and elders if they together went too far. He had likened the function of the ephors to a bridle or curb. Polybius changed the metaphor to one of a balance scale where the tendency of one pan to decline was counteracted by the weight of the other pan. The king and the people, he contended, naturally pulled in opposite directions and counteracted decline in each other as long as neither grew too strong. The third government in the mixture, the elders, for its part, having been selected on the basis of virtue, brought justice to the civic interaction. The elders swung from one side to the other to maintain a just balance and parity of authority between them. In substituting the analogy of a balance scale for the bridle he was, in effect, following Aristotle, who used the balance scale in his middle constitution as an analogy for the way that the shifting support of the middle people kept the extremely wealthy and extremely poor from going to immoderate excess (Arist. Pol. 4.11.1295b34-9). In Polybius’ view this arrangement produced the most enduring government known to him (6.10.11).
The Spartan mixed constitution could potentially have lasted forever; but having been constructed by an individual, it was also susceptible to being deconstructed by an individual. So it was in the third century bc, when Cleomenes abolished the mixed constitution and changed Sparta into a hellenistic autocracy, a tyranny on Polybius’ classification (2.47.3; 4.8.14). The Spartan constitution, the best and most stable the world had seen up to the third century bc, was nevertheless deficient in equipping the Spartans for conquering and ruling others (6.50). The Roman constitution surpassed it in just this respect.
The Roman constitution was a mixed constitution that evolved naturally. It arose by ‘‘many struggles and actions, in which the Romans repeatedly chose the better course, on the basis of a new understanding acquired in disasters’’ (6.10.14). Its constituent parts were comparable to those of the Spartan constitution: two consuls, embodying the monarchic form; the senate, embodying the aristocratic form; and the people. The political mechanism by which they interacted with one another, however, was different. Unlike the Spartan constitution in which the kings and the people prevented excessive growth in each other by opposition, with the elders switching from one side to the other to maintain the equilibrium, the Roman constitution prevented any part from carrying out its function without the cooperation of both the other parts. For example, the consul was responsible for leading the army and conducting warfare; but it was the senate that appropriated the money and that reappointed the consul as proconsul to continue conducting the war. The people, moreover, had to ratify or annul the consul’s action and arrangements (6.12,15). The consuls could not carry out their functions without the cooperation of the other two parts (6.13-14, 16-17).
As in Polybius’ analysis of the dynamic of simple constitutions, the operative factor in the cooperative functioning of the Roman mixed constitution was fear. An extreme threat compelled all to come to agreement and act in unity to meet the need of the hour, so that this particular form of government possessed irresistible power and achieved its every decision. It was also self-correcting, for when Rome became secure and prosperous and one of the governmental parts grew out of proportion and gained too much power, as governments tend to do, the others opposed it. This not only prevented the execution of self-interested actions, but the fear of intervention prevented even their proposal (6.18). Unlike the Spartan mixed constitution, the Roman constitution not only prevented degeneration, but also bonded the entire state together, directed all its force at its chosen objectives, and thereby enabled it to take control of an extensive empire.
When one looks more carefully at the construction of this union, one can see that just as in the case of the Spartan constitution, it comprised not merely three organs of government, but three governments, each consisting of a segment of the population along with its governing institutions. So, for example, the people as a governing body act through the election process, the popular courts, the council of the plebs and the tribunes with their vetoes (6.14-16). But the most revealing evidence for the relationship of the parts of the state to each other came in Polybius’ account of the decline of natural mixed constitutions (6.57.6-9). Polybius found a basis for his prognostication of the future of Rome in the history of the Carthaginian constitution, which was also a mixed constitution, but one that had already begun to decline by the time of the Second Punic War (6.51; cf. 6.52-6).
In his prognostication of the future of Rome Polybius articulated two additional laws of sociopolitical change, stipulating the conditions that would determine the decline of the mixed constitution (Hahm 1995: 41-5; 2000: 475-6). These differ from the laws that govern changes in simple constitutions precisely in the fact that they specify the change that will take place in two of the governments in the mixture, namely the government of the few (the aristocratic) and the government of the many, that is, the people. The outcome would depend on the interaction between them. As Polybius stipulated, prosperity affected the few and the many in different ways. It turned the aristocratic few to oligarchic greed and competitive display of wealth at the same time that it turned the democratic many to excessive love of political office, a characteristic of mob rule (ochlocracy). The greedy few alienated the people, making them ripe for revolt whenever they found a leader. At the same time, the people, now a deviant democracy, had many would-be leaders craving office, with leaders and people lacking the shared moral values of an improved constitution. When these masses revolted against the leadership of the now oligarchic few and refused to obey them, they de facto dissolved the mixed constitution. Since they themselves had already degenerated from democracy, their rule reconstituted the state as an ochlocracy or mob rule.
Most of Polybius’ political theory sounds as it if were being summarized from current thinking in the circles in which he moved, the elite families of Megalopolis and the leaders of the Achaean League; but there can be little doubt that his application to Rome and the Roman constitution was his own work. It showed most clearly how the mixture of a mixed constitution was assumed to work. It integrated three governmental structures so that they could cooperate with or oppose each other, while still remaining independent and subject to the natural laws of sociopolitical evolution and change.
World History
