The legislative power was there lodged in the _comitia centuriata_ and _comitia tributa_. In the former, it is well known, the people voted according to their census; so that when the first class was unanimous, though it contained not perhaps the hundredth part of the commonwealth, it determined the whole, and, with the authority of the senate, established a law. In the latter, every vote was alike; and as the authority of the senate was not there requisite, the lower people entirely prevailed and gave law to the whole state. In all party divisions, at first between the Patricians and Plebeians, afterwards between the nobles and the people, the interest of the aristocracy was predominant in the first legislature, that of the democracy in the second. The one could always destroy what the other had established; nay, the one by a sudden and unforeseen motion might take the start of the other and totally annihilate its rival by a vote, which, from the nature of the constitution, had the full authority of a law. But no such contest or struggle is observed in the history of Rome: no instance of a quarrel between these two legislatures, though many between the parties that governed in each. Whence arose this concord, which may seem so extraordinary?
The legislature established at Rome by the authority of Servius Tullius was the _comitia centuriata_, which, after the expulsion of the kings, rendered the government for some time altogether aristocratical. But the people, having numbers and force on their side, and being elated with frequent conquests and victories in their foreign wars, always prevailed when pushed to extremities, and first extorted from the senate the magistracy of the tribunes, and then the legislative power of the _comitia tributa_. It then behoved the nobles to be more careful than ever not to provoke the people, for beside the force which the latter were always possessed of, they had now got possession of legal authority, and could instantly break in pieces any order or institution which directly opposed them. By intrigue, by influence, by money, by combination, and by the respect paid their character, the nobles might often prevail and direct the whole machine of government; but had they openly set their _comitia centuriata_ in opposition to the _tributa_, they had soon lost the advantage of that institution, together with their consuls, prætors, ediles, and all the magistrates elected by it. But the _comitia tributa_, not having the same reason for respecting the _centuriata_, frequently repealed laws favourable to the aristocracy; they limited the authority of the nobles, protected the people from oppression, and controlled the actions of the senate and magistracy. The _centuriata_ found it convenient always to submit; and though equal in authority, yet being inferior in power, durst never directly give any shock to the other legislature, either by repealing its laws or establishing laws, which, it foresaw, would soon be repealed by it.