Rome, the city-state on the Tiber River, like her counterparts in Greece, had no cohesive written constitution. There were the Twelve Tables from around 450 B.C., of which mere fragments remain, which are sometimes presented as the Roman Republic’s constitution. However, the tablets were more an attempt to codify certain principles of criminal and civil law, rather than to lay the foundation for a political system. However, they did begin the practice in Roman law of published codes enacted by a legislative body and accessible to all citizens, which remained a core characteristic of European legal systems influenced by Rome.

Much of Rome’s political constitution by contrast was the product of custom. That custom evolved through responses to changes in the society’s social structure, through the citizens’ tacit acceptance of political bodies that arose from critical events, and by incorporating founding legends. An example of the first was the change in sources of wealth and the nature of the aristocracy comprising the leading families. The second would include the expulsion of Rome’s last king, the Etruscan Tarquin the Proud, at the end of the 6th century B.C. That event resulted immediately in the preeminence of the established aristocratic council, the Senate, and, a half-century later, in the emergence of the assemblies as sources of political influence for the commoners. The last would be the creation of institutions (such as the Senate and the tribunes) and practices said to go back to the 8th century B.C., and the acts of Rome’s first king, the legendary Romulus, and his successor, the Sabine Numa Pompilius.

While the writings of historians such as Livy and Sallust and political leaders such as Cicero are instructive, the single most authoritative source for the Roman constitution is its earliest expositor, the great Greek historian and father of constitutional analysis, Polybius of Megalopolis. Born in 200 B.C., he became a prominent politician in the Achaean League, of which his city was a member. The League, had for some years, had to tread a narrow path in relations with Rome, by then in control of most of Greece. With some exceptions, the leaders of the Greek cities generally were less than thrilled about Roman control. Such lack of enthusiasm raised suspicions and put those politicians in potential danger.

After Rome in 168 B.C. defeated Macedon for the third and final time, the Senate decided to break up that kingdom into four tributary republics. Rome also “went Roman” on the Greeks allied with Macedon, destroying 70 towns in the region of Epirus and selling a reported 150,000 into slavery. Rome’s Greek “allies” fared better but were disciplined for their lack of commitment. Polybius was among the 1000 Achaean leaders suspected of “fence-sitting” who were deported. Most were sent to provincial towns away from Greece.

Polybius was allowed to stay in Rome itself, due to the intervention of two powerful Roman leaders, Scipio Aemilianus and his brother. The developing friendship between Scipio and Polybius gave the latter access to the Roman elite. His learning and gregarious and active personality further solidified those connections. Polybius, in turn, became a committed advocate for the city and its system of government. As well, his favored status gave him extensive freedom to travel. When the Senate authorized the Greeks to return to their cities, Polybius declined. Instead, he eventually accompanied his friend Scipio to North Africa when the latter was given the command of the army sent to destroy Carthage in the Third Punic War. Polybius was well acquainted with Rome, its history, and its institutions, and he wrote about them with affinity.

The Histories is Polybius’s major influential work. It was a massive undertaking of 40 books, although one needs to keep in mind that the physical limitations of papyrus scrolls meant that a “book” might be more like a quite lengthy chapter today, and the entire effort perhaps a couple of thousand pages. The first five books are fully available, with more or less extensive excerpts from many others. Some are entirely lost. Most of the work covers Roman history from the Second Punic War (against Hannibal) to Polybius’s time. Most important to constitutional analysis is Book 6, the numerous preserved fragments of which cover, in the estimate of one authority, about two-thirds of the book. Missing is a thorough analysis of the Roman assemblies, in contrast to his discussion of other elements of the Roman constitution.

The constitution Polybius describes is that of his time, after Rome has finalized its drive for dominance of the Mediterranean world. The Punic Wars lie in the past, Carthage has been eradicated, and the destructive Social Wars and civil wars are in the future. Romans’ confidence in their institutions is high, and the republic which Polybius describes is at its political zenith. As was the habit of classic Greek observers of political systems, Polybius believed in a duality of good and bad forms of government, with an inexorable process of degeneration between those forms. But, unlike, for example, Plato and Aristotle, he claimed to see in the Roman constitution a system resistant to such degeneration. He also observed that states commonly moved through those forms sequentially and even attempted an anthropological explanation for the origins of government. Thus, he argued an archaic form of monarchy emerged when the physically dominant member of a primitive band of humans took command.

As societies become more sophisticated, that archaic form of tribal leadership proves inadequate. A more stable form of kingship emerges, one based on reason and excellence of judgment, which, in turn, fosters consent of the governed. Initially, such kings are elected for life. Eventually, the dynastic impulse of rulers to pass their office from father to son leads to kingship often becoming hereditary. Over time, such dynastic succession induces a sense of superiority and entitlement, which results in formal distinctions and ceremonies to set the royals apart from commoners. Worse, these royals begin to consider themselves exempt from rules and morals. As ordinary people begin to react with disgust at such licentiousness and arrogance, the ruler responds with anger and force. Thus, the inevitable outgrowth of kingship is tyranny.

The wealthy and talented members of respected families chafe at the tyrant’s rule the most. Conspiracies develop and the tyrant is replaced by a ruling class of high-minded men, the aristocracy. Recalling Plato’s criticism of oligarchy, Polybius saw the degeneration as the fault of the sons, not the fathers. As he wrote, the descendants “had no conception of hardship, and just as little of political equality or the right of any citizen to speak his mind, because all their lives they had been surrounded by their fathers’ powers and privileges.” Soon enough, the government controlled by supremely moral and wise men gives way to a self-interested oligarchy “dedicated … to rapaciousness and unscrupulous money-making, or to drinking and the non-stop partying that goes with it ….”

The general populace, encouraged in their passions by manipulative leaders, murders or banishes the oligarchs and itself takes on the responsibilities of government. Democracy, according to Polybius, is based on majority rule, but a majority tempered by “the traditional values of piety towards the gods, care of parents, respect for elders, and obedience to the laws.” This sounds strikingly like the admonition of republicans through the ages, that self-government requires self-restraint, focus on the common good and general welfare, and a strong moral and religious framework to promote republican virtue. John Adams’s observation that the American system was fit only for a moral and religious people is one example particularly relevant to the American experience. The exhortation in the third article of the great North-West Ordinance of 1787, about “Religion, morality, and knowledge being necessary to good government and the happiness of mankind” is another.

Regrettably, such values prove to be in short supply, and the population of the democracy, now encouraged in their delusions by manipulative politicians, believes instead that it has “the right to follow every whim and inclination.” Those ambitious for power and wealth seek to get ahead by corrupting the people with money to obtain their support. The common people become greedy for such largesse, and democratic self-government degenerates into ochlocracy (“mob rule”). As Polybius described the fate of democracy, “For once people had grown accustomed to eating off others’ tables and expected their daily needs to be met, then, when they found someone to champion their cause … they instituted government by force: they banded together and set about murdering, banishing, and redistributing land, until they were reduced to a bestial state and once more gained a monarchic master.” This is the predictable and depressing lifecycle of political systems. Polybius would have nodded knowingly, had he been present at Benjamin Franklin’s reply to his interlocutor about the type of government produced at the Philadelphia Convention, “A republic, Madam; if you can keep it.”

Fortunately, such a cycle of corrupt and degenerate forms of government could be avoided, and Rome showed the way. Polybius exalted Rome as a “mixed” government, composed of essential elements of all taxonomic forms, monarchy, aristocracy, and democracy. Unlike Plato’s fictitious ideal republic, Rome’s was a functioning system which had proved its mettle for centuries. Unlike Aristotle’s description of the Athenian government as a workable, but uneasy, mixture of popular and oligarchic elements in the Assembly on one side and the Council of 500 and other institutions on the other, Rome succeeded because of its more developed balance of powers. In that, according to Polybius, Rome’s constitution resembled that of Sparta, although Rome’s developed by natural evolution rather than from a conscious decision by a wise lawgiver like the mythical Spartan Lycurgus. Polybius regarded Sparta’s system as particularly enlightened and wrote with great favor about it, although he recognized that the structure did not prevent Spartan hubris from engaging in ultimately disastrous foreign military adventures. In light of Sparta’s legal totalitarianism, it is ironic that Polybius ascribed to this mixed government a long history of liberty in Sparta. Perhaps by this he meant independence. In any event, his characterization of mixed government became the classic understanding of what today would be called a system of limited government.

The preeminent political institution of the Roman Republic was the Senate. Although eligibility changed over time as membership was opened up to the more prominent plebeian class, the equites ((knights), the Senate was primarily the institution of Rome’s aristocratic families, the patricians. The body had begun as a council composed of 100 men chosen by Romulus from the leading land-holding families as city fathers (“patres“). Initially, it was solely a hereditary body, but eventually the primary determinant, if one sought admission to the Senate, became landed wealth. The Senate had the power over appropriations. The civil functionaries had to obtain Senate consent for all expenditures, most importantly for the massive funds spent every few years on the repair and construction of public buildings. Major crimes, such as treason, conspiracy, and gang murder were under Senate jurisdiction. Foreign relations, colonial administration, and matters of war and peace were the domain of the Senate.

Striking about the Senate was that it had no formal role except to act as an advisory council, the same as under the earlier monarchy. In reality, it was the single most powerful body in the republic, due to its class ties and consciousness, its continuous sessions, and its life membership. Moreover, the mos maiorum (the “custom of the ancestors”), the powerful force of tradition in the Roman constitution, sustained the legitimacy of the Senate. A senatus consultum was merely an advisory opinion by the Senate, but such an opinion was required for any law proposed for adoption by an assembly. Although a consultum could be overridden by the assembly or could be vetoed by a plebeian tribune, in reality an unfavorable consultum usually spelled the end of the proposed law or, if enacted, caused it not to be enforced by the magistrates. Polybius noted, if one were to look solely at the Senate, one would believe that Rome was an aristocracy. Or, in the more jaundiced view of some historians who claimed that the Senate was actually controlled by a tightly knit small hereditary group of families, it was an oligarchy.

There was also, however, another long tradition in Rome’s constitution, “What touches all must be approved by all.” As Cicero put it in Republic, “res publica, res populi.” The consent of the people was given through the assemblies. Polybius described their role in assessing taxes, the ratification of treaties, actual declaration of war, and confirming the appointment of officials. Moreover, the people had a role in legal processes. All death penalties had to be approved by an assembly. The same held for more general criminal cases where a substantial fine would be imposed. He concluded that, from this perspective, one might declare Rome a democracy.

There were various assemblies over time, and Roman citizens could attend any. Histories does not have much discussion of them. This might be because Polybius was not a great admirer of those bodies or, more simply, because his discussion is in the chapters which have been lost. These explanations are not contradictory, and there is evidence for both. One such body was the Centuriate Assembly, the oldest. It can be traced to a 6th century B.C. king and was modeled on the centuriae, the military units of 100 infantry and 10 cavalry that each of the ten subunits of the three “tribes” of Rome had to provide. As in Athens, these tribes were not based on ethnicity but were simply geographic constituencies within the city.

As the city grew, so did the number of tribes and the size of the voting units. For a long time, there were 193 “centuries.” They were organized on the basis of land ownership, wealth, and age, which, in turn, was related to the type of military service and associated weaponry of the members. At the top were the equites (knights), who were wealthy enough to provide horses and served in the cavalry. They had 18 centuries. Next were 170 centuries for the infantry, divided further into five classes based on their members’ wealth and weaponry. Below them were five centuries for the proletarii (the poor), those who could not supply weapons and typically were assigned to the navy.

In contrast to the Athenian ekklesia, in the Roman system the citizens did not vote simply as individuals. Although they met in the same place, the actual voting took place within their respective centuries. Each century had one vote, determined by the majority vote of citizens assigned to that century. The Assembly’s approval depended on a majority vote of the centuries, not of the undifferentiated citizens. With 193 centuries, the votes of majorities in 97 of those centuries would be required to approve a measure. In fact, voting was heavily skewed in favor of the equites and the wealthiest layer of the others. Between them, they were assigned 98 centuries, on the reasoning that those who provided the most financial support and had the most to lose in military service should have the most influence. Moreover, voting was done in class order, with the centuries of the equites voting first, those of the wealthiest class of others voting next, followed by the next lower group, and so on. The poor voted last. As a result, the vote of the poor rarely mattered. Class solidarity, the number of centuries weighted towards the wealthy, and the staggered voting meant that most issues would be decided well before the smaller landowners or the poor voted. Even the reforms of the 3rd century B.C., which expanded the number of centuries for the landowning classes to 350, had little effect on the dominance of the wealthy.

The Assembly could only consider bills which were on the agenda set by the tribunes or the magistrates. The citizens could vote on the proposal but not debate the bill at issue or offer amendments. Finally, all voting was done in the city of Rome. As the city’s domain spread, it became more difficult for any but wealthy citizens to travel to Rome for the duration of the Assembly’s legislative or appointive tasks. Based on his analysis of the system, the historian Scott Gordon doubts that even one-tenth of the 400,000 Roman male citizens at the end of the 2nd century B.C. attended a voting assembly in their lifetimes. The formal powers of the Assembly eventually were transferred to the Senate by the Emperor Tiberius.

There was, however, one mechanism by which the public could express its views, the contio. After a bill was proposed by a tribune, there had to be a period of at least twenty-four days before the Assembly could vote on it. This allowed for informal discussion among citizens of the bill’s merits. Moreover, any tribune could call for a formal meeting, the contio, which all residents, including women, foreigners, and slaves, could attend. The only speakers permitted were those selected by the presiding tribune and usually were senators or various magistrates. Public comment was limited to shouts and other sounds indicating support or opposition.

The final part of the formally operating civil government were judicial, executive, and administrative officials. Chief among them were those sought by ambitious Romans embarked on the cursus honorum, the “path of honors” along a sequence of offices, the apex of which was the consulship. All were initially open only to those of senatorial rank, but eligibility was expanded in the 4th century B.C. In practice, only scions of the wealthy families were likely to be elected, especially as consul. Thus, Cicero, a non-patrician resident of a non-Roman town in Latium and member of the knightly class, the highest of the plebeian classes, climbed this ladder of success quickly.

Election to these offices was by the Assembly for a one-year term, with minimum age requirements. The lowest office was that of the quaestor, who had to be 30 years old and have completed several years of military service. Quaestors were in charge of financial administration, a source of influence for further political advancement, and of record-keeping for the state archives. Above the quaestor was the aedile, in charge of public facilities and public festivals and celebrations. The next rung in the ladder was the praetor, a multi-function office. Praetors performed judicial functions but also could step into the executive role of consul if both of the consuls were absent from the city. As jurists, praetors had significant influence on the development of the body of Roman law. After his term ended, a praetor could also be awarded a foreign post as propraetor. This included military power, with full governing authority in the province. There was no term limit for that office.

At the end of the cursus honorum beckoned the consulship. The Assembly elected two consuls each year, at least one of whom was usually engaged in military campaigns in the provinces, the consul peregrinus. The one in Rome, the consul urbanus, had no real military function, because armed forces had to be kept some distance from Rome during peacetime, a constitutional limit broken, for example, by Julius Caesar when he crossed the Rubicon River. The consul’s position in the Republic was one of influence, not formal power. Any executive decision could be vetoed by the other consul and any of the ten plebeian tribunes, Moreover, he could not override the actions of other magistrates. However, his status as a member of a leading family and constant interaction with the Senate, plus the fact that he had survived the competition to reach the apex of the cursus honorum gave his opinions and actions great constitutional legitimacy. After his one-year term ended, a consul could not be re-elected for at least ten years, until the general Marius destroyed that informal constitutional limit in the 1st century B.C. After his term, a consul could be elected as proconsul, the highest military and administrative position in the provinces, with no term limits. This usually arose from the extended military campaigns abroad, which necessitated continuity of command.

Finally, outside the formal cursus honorum were the tribuni plebis, ultimately ten in number, who originally represented the “tribes” or sections of the city. Tribunes spoke for the political interests of the plebeians. They were elected to one-year terms by the Assembly. In that capacity, they were responsible to assist any plebeian who had been wronged by a magistrate. This included the power to overrule an unjust judicial order of punishment. The tribunes’ political power extended to vetoing any bills proposed to the Assembly by other magistrates and to consulta of the Senate deemed contrary to the plebeians’ interests. Eventually, they became members of the Senate and set the agenda for that body. While they formally represented the plebeian classes, with some exceptions such as the famous Gracchi brothers, they were no radicals. They were typically drawn from the patricians and the knights, the high-status classes, and shared their interests. As well, their potentially significant power was impeded by the fact that any affirmative act of a tribune could be vetoed by any of his nine colleagues. In reality, tribunes could act as a shield for the commoners against the wealthy, but rarely as an effective sword to advance the interests of the lower classes in opposition to the wealthy.

One additional aspect of the Republic’s constitutional practices bears mention. Every system has to deal with the state of emergency that can arise over time, the most common of which is war, either foreign or civil. For a long time, in such exceptional circumstances the Roman Senate would formally appoint a dictator to rule by decree for six months. That practice was discontinued by the end of the 3rd century B.C. Instead, during later troubles, such as those of the civil wars of the 1st century B.C., such exceptional powers would be authorized under the terms of a senatus consultum ultimum, a “final act of the Senate” needed to protect the Republic.

Polybius saw in the structure of the magistracies, especially in the consuls, the monarchic element that was part of the “balance” in the Republic’s constitution. In the various interactions of Senate, Assembly, and tribunes, and in their mutual formal and practical limitations, he perceived a system of “checks” on the power of any of them. In some of the particulars, he was off the mark. For example, unlike the Spartan kings to which he compared the consuls, the latter served for only one year, not life. Moreover, the consuls lacked the formal powers one normally associates with kingship. On the whole, however, his assessment has merit.

Historians have long debated the causes of the Republic’s demise. There is certainly no reason to limit the matter to one such cause. Among them was the collapse of broadly-distributed land ownership which sustained a “middle class” in an agricultural republic. As the wealthy became more so regardless of the source, they bought up more land. Land was a reflection of one’s status. Indeed, because commercial ventures were formally prohibited for Senators, one needed land to join that body. The demand raised the price of land and the taxes imposed on it. The growth of these large latifundia drove the previous smaller landowners into the city. There, they became part of the urban proletariate and competed for employment with the large and growing number of slaves acquired through foreign conquests and with other foreigners attracted to the increasingly imperial city.

Another cause was the opportunity for power and wealth afforded to successful generals operating as proconsuls in the provinces. With the troops often ill-paid by Rome, local taxes were extracted by these commanders and used to pay the troops directly. Loyalties became redirected from the city to the commander. The republican slogan SPQR (Senatus Populusque Romanus), “the Senate and the People of Rome,” which appeared on the standards of the legions, was supplanted by the reality that, “You take the king’s silver, you become the king’s man.” Especially as those troops were increasingly formed from poor Roman volunteers or foreigners, especially after the military reforms of Gaius Marius around the turn of the 1st century B.C., it became easier for generals to use those professional troops—or threaten to do so—against the city itself and to rule by force. Marius himself, and his erstwhile protégée Sulla, set unfortunate examples.

Perhaps most significant was the fundamental change in the political and social conditions of Rome. Consistent with Polybius’s theory, the societal degeneration about which he had warned as the inevitable result of the democratization of politics and the weakening of the population’s character brought about thereby, in fact occurred a couple of generations after his death. The impoverishment of a large portion of society and the resultant dependency on public largesse for survival, made those citizens susceptible to the slogans and programs of the populares, such as Julius Caesar and other, more dangerous demagogues. The bloody competition among families of the oligarchic upper classes, as shown in the Social Wars and the proscriptions of the military commanders Marius and Sulla, contributed to the chaos which sent the Republic on the path to the monarchy of the Empire.

The same events that brought about that radical social transformation also manifested themselves in the essential incongruity of governing a huge multi-cultural empire through institutions designed for a small city-state on the Tiber River. The notion of “community,” with shared traditions, civic and religious, and an ethic of sacrifice necessary to sustain the civic engagement at the core of real self-government, is eroded in the chaos of ethnic, linguistic, religious, and cultural diversity and the impersonality of large numbers. Had the Roman elite been willing to open up its political institutions and to extend citizenship and formal participation in the political system to all parts of their domain sufficiently and in a timely manner, a republican structure of sorts might have survived. As it was, the city had become an empire in fact well before its political structure changed from Polybius’s republic to Octavian’s monarchy.

Joerg W. Knipprath is an expert on constitutional law, and member of the Southwestern Law School faculty. Professor Knipprath has been interviewed by print and broadcast media on a number of related topics ranging from recent U.S. Supreme Court decisions to presidential succession. He has written opinion pieces and articles on business and securities law as well as constitutional issues, and has focused his more recent research on the effect of judicial review on the evolution of constitutional law. He has also spoken on business law and contemporary constitutional issues before professional and community forums, and serves as a Constituting America Fellow.

Click here for American Exceptionalism Revealed 90-Day Study Schedule
Click here to receive our Daily 90-Day Study Essay emailed directly to your inbox