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'. (more)
Where do the analogies between Rome and an Australian Republic coincide. Pax Romana was real, and Italy did benefit from the Roman commercial and civil view of citizenship and half-citizenship. Prior to Roman dominance of Italy there was constant warring between city-states, tribes, towns and the immigration of Gauls from the north. Rome's military extension halted the incursion of this violence - this is the Roman Peace or pax Romana.

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In parallel to the military campaigns of the early republic, the constitution during that time was largely class based. H.H. Scullard argues that early republican Rome was two states; a plebian state and a patrician state. These states did not become unified until after the Gauls seized Rome; when the patricians and plebians became a unitary Roman state. (more)
Cam Riley: South Sea Republic. Freedom, liberty, equity and an Australian Republic.