Having removed a king, the Romans had to give somebody his powers, and the entire constitution is a set of answers to the question of how to do that safely.
The previous lesson left the Republic with an inheritance: imperium, the auspices, a Senate and an assembly, all working, none designed for a state without a monarch. This lesson describes the machine that resulted. There was no constitutional text, no court to interpret one, and no way to amend it other than passing a law or, more often, doing something and finding that nobody stopped you.
Four constraints on one power
Roman magistrates held imperium in full. What the Republic did was surround it with four constraints, each simple and each aimed at the same target.
The first is collegiality. Every office had at least two holders, and each held the whole power rather than half of it. Two consuls did not divide imperium between them; they each had all of it, which meant either could block the other by the plain method of ordering the opposite. In the city they alternated the fasces month by month so that only one set of lictors walked in front of a consul at a time.
The second is annuality. A magistracy lasted twelve months, after which the holder was a private citizen again, liable to prosecution for what he had done in office. Nothing concentrated Roman political minds like the prospect of a year ending.
The third is provocatio, the citizen's right of appeal to the people against a magistrate's coercion. The tradition dates it to 509 and repeats it in 449 and 300, which suggests a rule that needed constant reassertion. It applied domi, at home, inside the sacred boundary of the city, the pomerium, and not militiae, in the field, where a commander could flog and execute at will. The boundary is what forced a general to lay down his imperium before entering Rome, and it is why a man who kept an army and crossed that line was not making a political error but committing a defined constitutional offence.
The fourth is the veto. Any magistrate could block an equal or lesser one, and the ten tribunes of the plebs could block almost anything, including each other. A veto needed no reason.
Add these up and the system's default is inaction. Anything that happens has to survive a colleague, ten tribunes, the calendar and the auspices, and Roman politics is mostly the story of what could be pushed through that filter.
Example. If two consuls each held the whole of imperium, why did the Republic also need a dictator?
Because the constraints that make an ordinary year safe make a bad year fatal. A blocked pair of consuls produces no decision, and when a hostile army is four days' march away, no decision is the worst available one. So the Romans built an escape hatch with its own limits: on the Senate's advice a consul named a single dictator, who held undivided imperium with twenty-four lictors, was not subject to a colleague's veto, and held office for a maximum of six months or until the task was done. The fear of one-man rule was met by time, not by division. That the office was used repeatedly in the fourth and third centuries BC and then abandoned after 202 BC is itself informative: the escape hatch was for emergencies of weeks, and the problems of the later Republic did not have that shape.
Now you. Provocatio protected a citizen inside the pomerium and not outside it. What follows for a commander who wanted to keep his army and stand for office at the same time?
Answer
He could not do both. Standing for office required his presence in Rome as a private candidate, and entering Rome required laying down imperium, after which he had no army, no immunity and no protection from prosecution by the enemies he had made. Staying with the army kept him safe and kept him out of the election. The rule was written for a city-state whose commanders were a day's ride away, and it turned into a trap once commands ran for years at the far end of the Mediterranean. That trap is the direct cause of the crisis of 49 BC.
The ladder
The offices were arranged in an order of increasing seniority, the cursus honorum, with minimum ages fixed by law. The lex Villia annalis of 180 BC set them, on the usual reconstruction, at 39 for the praetorship and 42 for the consulship; Sulla later put the quaestorship at 30 and made it the compulsory first step. Two years had to separate one office from the next and, in principle, ten years had to separate two consulships.
A quaestor handled money, in the treasury at Rome or as a governor's finance officer, and the quaestorship became the door into the Senate. An aedile ran the city, its markets, streets, water and games: no power and enormous visibility, since the games came partly out of his own pocket and were remembered at the next election. A praetor held imperium, presided over the courts and could command an army. A consul was head of state for twelve months and gave his name to the year. Two offices sit outside the ladder. The censors, two of them elected every five years for eighteen months, took the census, assigned every citizen to a class and a tribe, revised the roll of the Senate with power to strike a man off it for conduct, and let the great public contracts. The dictator was the emergency device described above.
Now the arithmetic, using Sulla's numbers. Twenty quaestors were elected each year, eight praetors, two consuls. Of a cohort of twenty entering the Senate, at most eight could reach the praetorship and two the consulship, so ten per cent of those who started the climb finished it, and the true figure is worse because some consulships went to men holding a second one. That is the mathematical fact behind everything else in this course. The Roman aristocracy was not a group of colleagues sharing power. It was a permanent tournament with two winners a year, in which the accepted way to distinguish yourself was to win a war, and in which a man with no prospect of the consulship might prefer to break the rules than to lose politely.
The Senate: authority without power
Read the Senate's formal position and it looks trivial. It was not elected. It passed no laws. It gave advice, and its resolution was a senatus consultum, a consultation, which a magistrate was free to ignore. It could not levy a tax, declare a war or convict a citizen.
Read what it actually did and it ran the state. It assigned provinces to magistrates, received foreign embassies, authorised spending from the treasury, decided how many legions to raise and where they went, appointed commissions, prorogued commands and set the agenda for the assemblies through the magistrates who were themselves its members. In the second century BC no important decision was taken without it.
The gap between those two paragraphs is the most instructive thing in the Roman constitution, and it has three causes.
The first is continuity. A consul had twelve months; a senator, enrolled at about thirty and serving until death, had perhaps thirty years, so the standing body outlasted every magistrate by a factor of around thirty to one. The men who knew what had been agreed with Massilia in 154 BC were sitting in the chamber, and the consul was not.
The second is money. The treasury sat in the temple of Saturn under quaestors, and the convention that only the Senate authorised withdrawals meant a magistrate with an idea and no money had an idea and nothing else.
The third is that the Senate was the pool the magistrates came from and returned to. A consul spent one year above the Senate and the rest of his life inside it, judged by the men he had overruled. Ignoring a senatus consultum was legal and expensive.
Example. After Sulla, twenty quaestors entered the Senate each year and the chamber held about six hundred members. What does that imply about how long a senator served, and does it hang together?
If the size is steady, entries must match departures, so 600 divided by 20 gives a mean tenure of 30 years. A man entering at the legal minimum of 30 would then be leaving at about 60, by death or by a censor's mark. That is consistent with ancient life expectancy for a man who has already survived to thirty, so the numbers hang together. Try it with the pre-Sullan figures and it does not: 300 senators fed by eight quaestors a year implies 37.5 years of service, ending at 67, which is too long. The mismatch is a real one, and it is the reason the pre-Sullan censors also enrolled ex-tribunes and ex-aediles, and why the chamber often sat below its notional strength.
Now you. A tribune proposes a law the Senate hates. The Senate passes a resolution against it. The tribune puts it to the assembly anyway and it passes. Is it law?
Answer
Yes. After the lex Hortensia of 287 BC a measure carried in the plebeian assembly bound the whole people, and no senatorial resolution could annul it. Everything the Senate could do about such a bill was informal or indirect: persuade another tribune to veto it, have an augur report unfavourable omens, delay it to the end of the year, or wait and prosecute the proposer once his immunity lapsed. That is exactly how the fights of 133 and 123 BC were conducted, and it is why those fights, when the informal levers failed, ended in killings rather than in rulings.
The assemblies, and what they could not do
Every law and every magistrate came from a vote of the citizens, which sounds like a democracy until you look at what a Roman assembly was allowed to do.
It could not debate. It could not amend. It could not meet on its own initiative. A magistrate summoned it, put a single question, and it answered yes or no, having heard whatever speakers that magistrate chose to allow at the informal meeting beforehand. There were three of them in practice: the comitia centuriata, organised by property and originally by military class, which elected consuls, praetors and censors and formally declared war; the comitia tributa, organised by the thirty-five tribes, which elected the lesser magistrates and passed laws; and the concilium plebis, the plebeians alone by tribe, which elected the tribunes and passed the plebiscites that after 287 BC were law.
None of them voted as individuals in a single pool, and the consequences of that are so large that the next lesson but one is devoted to them.
Polybius on the mixture
The best ancient analysis is Polybius's sixth book, written in the 150s BC for Greek readers who wanted to know why Rome kept winning. His answer is that Rome had accidentally achieved what Greek theory prescribed: a mixed constitution, monarchic in the consuls, aristocratic in the Senate, democratic in the people, each element able to obstruct the others and therefore obliged to co-operate.
He argues it concretely, which is what makes it good evidence. A consul commands in the field, but his supplies and his soldiers' pay are voted by the Senate, and after his year another man can replace him. The Senate controls the money, and the great censorial contracts for harbours, mines and taxes are held by companies of citizens who sit in the assemblies. The people elect and legislate, and depend on the Senate for the wars and settlements that shape their lives.
Two cautions. Polybius describes the system at the moment of its greatest success, and a theory of balance looks convincing when the state it describes has just beaten everyone. He is also a client of the Scipios, disposed to see aristocratic guidance where a hostile witness would see aristocratic control.
Example. Polybius says the people are sovereign because they elect magistrates, pass laws and try capital cases. Test the claim against the machinery just described.
The powers are real: no man held office without a vote, and no law passed without one. The limits are equally real. The people could not propose, amend or debate a bill, and could not meet unless a magistrate called them; the choice at an election was between candidates the presiding magistrate had accepted, drawn almost entirely from families already in the Senate; and the agenda was set by men whose careers depended on senatorial goodwill. Sovereignty of that shape is a veto over the aristocracy's proposals rather than a capacity to govern, which is a genuine power and not the one the word usually implies.
Now you. Polybius wrote that no element could act without the others, and inferred stability. What later event tests the inference hardest?
Answer
The tribunate of Tiberius Gracchus in 133 BC, about twenty years after Polybius wrote. A tribune used the people's undoubted legal power to legislate against the Senate's undoubted informal control, and the machinery had no rule for deciding between them, because it had never needed one while the two sides agreed. Polybius's balance depended on a shared willingness not to press any lever to its limit; it described a political culture more than a mechanism. When men appeared who were willing to press, the constitution turned out to have no answer inside itself, and the answer came from outside it, in the form of a mob with clubs.
What the machine could not do
Notice what the design assumes. Every magistrate is in Rome or a few days from it. Every command is short. Every officeholder returns to the body he came from. Every dispute is settled by men who expect to see each other next year.
None of that would be true of the state Rome became, and the rest of this course is the story of the assumptions failing one by one. But the first pressure on the machine came from inside the city and much earlier, from citizens who noticed that all these carefully divided offices were held by the same fifty families, and who spent two centuries prising them open. That is the next lesson.