Mos is one of the latin words the Roman used for constitutional tradition. One of the curious natures of the Roman Constitution and legal system was how unwritten it was. Much of it was ius , which me might call customary, to mos which Lintott describes as 'the way things were done at the time'.

Most Romans were illiterate, unlike modern Australia which is a literate society. So written laws were mainly of value to the Magistrates, rather than the population. However, despite Australia's high literacy rate, you could probably count the people who actually read the laws or legislation in Australia on one hand.

I am willing to bet that even in the modern Auian political blogosphere there are very few who read legislation directly, and if they do, it is probably only one or two statutorial tracts.

The benefits of written law are at their most valuable when appealing to the judicial. They are also at their best in restricting the actions of public positions from arbitrary to regulated.

Tacitus wrote that when there was bad public administration in Rome a flurry of laws would come soon after from the Tribunes and assemblies - most of which were aimed at restricting the actions of the magistrates.

Another reason for the lack of written laws may have also been because criminal law was dealt with as a civil matter. There were no public prosecutors in Rome as we know them today in our legal system.

However, written laws were inscribed into brass plates and placed in prominent public places, such as temples and obelisks, in Rome, and the other Roman cities, so that the law was widely known. Many of the archaeological evidence for Roman law comes from these brass tablets.

Mos was intended to have the force of history - but again, we find it relieved from any binding force as the liberty of the sovereign under mos is deliberately for creating new convention. It is presumed that the sovereign's action will create a new contiguous force of custom; but again, that new precedent, and even precedent before it is subject to the whim of the sovereign.

It could be glibly argued that Mos led to the abuses of consulships, and pro-consuls and pro-praetors in the provinces, not to mention the new traditions of dictators and tribune that led to the Augustan empire. Then again, the counter argument is that Mos enabled plebian law to bind the patricians, and defeat the worst excesses of classism between Roman citizens (sucked to be a slave though pretty throughout Roman history).

The mistake is to read the Roman Constitution as a liberal democratic one. Basically, the Roman Constitution is from antiquity, and prior to the enlightenment. Rome was a martial-state and its constitution was a martial one. It political, social and economic structures were designed for martial success.

Mos, as a Roman institution, has to be seen within that framework. Most of the expansions of constitutional practice, especially the negative, in Rome were claimed under emergency. The tumult of war and violence was seen as a valid method to make the Roman Constitution reactive - the problem is, as Cicero found out, once the genie is out of the bottle it will not go back in.

It becomes expansive and not contractive; new powers, hard won, are rarely given up. Cincinnatus is the myth that says they are; Rome is the history that says they are not. It did not halt Roman military effectiveness, but did make the Roman political system more arbitrary.

From a liberal democratic point of view that is horrifying, but from a martial-state's point of view, it is probably just mos in action, and despite the lament for the republic by the likes if Cicero and Brutus, consuls continued to have military success under empire, the losers were the oligarchs, whose main political power was through the Senate and its feeder magistracies.

After Tiberius politics becomes arbitrary as well, mos compounds mos. Where once imperium hand over was consistent and ordered through the elections of consuls, praetors and tribunes each year; it was replaced with dynastic or violent passage of power from one Emperor to another with the support of the Senate or Pretorian Guard.

Violence and civil war replaced elections.

More Reading on Rome

• Rome
• Mos
• Andrew Lintott
• martial-state
• Book Review: Cicero
• Cicero on Being a Public Figure
• The Roman Constitution
• Augustus, Constitutional Change and Moralisation
• Meaning Whatever They Want
• Roman Names
• Regal Rome
• Provincia - Roman Separation of Magistrates
• Roman Factio
• The Military Campaigns of the Early Roman Republic