The Romans, according to the Histories of Polybius, had three forms of government, though the Roman constitution was never codified as a written document. All the functions were distributed among the three so equitably that it was impossible to establish whether Rome’s government was monarchic, aristocratic or democratic.
Polybius shows which functions pertain to each form of the government. Thus, the Consuls represent the monarchic element, the Senate the aristocratic, and the people the democratic. This state of affairs was characteristic of the golden age of Rome and, with some changes, persisted to Polybius’s times.
All people and all officials, except the tribunes of the people, are in subjection to the Consuls. They report to the Senate on all matters, present envoys to the Senate, and are responsible for carrying out the Senate’s decrees (Book 6, chapter 12). They also convene assemblies and have unlimited authority in matters of war. They can subject to punishment anyone under their authority and can spend the public money as they see fit.
The Senate is primarily responsible for managing the treasury. All crimes committed in Italy that require public investigation (such as treachery, conspiracy, mass poisoning, and gang murder) are within the Senate’s jurisdiction (Book 6, 13). Also, the Senate’s job is to send missions outside Italy and receive missions from other lands. Polybius stresses that the people have no share in any of the above-mentioned functions.
However, the people do have a very strong influence on the Roman state, because they control rewards and punishments. (Book 6, 12). In Polybius’s views, these factors are so important as to determine the whole of human life:
There is no other provision within the constitution for these functions, but without them human life itself has no coherence, let alone governments and constitutions (Book 6, 14).
The people’s prerogative is to deal with cases when the penalty of the offense is a substantial fine, especially when the accused are high-ranked officials, and all death penalty cases. The people also decide whether to go to war, and they ratify or abrogate alliances (Book 6, 14).
Polybius’s goal is to show that there is equipoise between these three forms, because, by competing, they balance one another. In his portrayal, Rome is a state with an ideal government.