In practice the Roman people were willing to allow the Senate and magistrates to conduct a large part of the business of the state, but in theory they claimed to represent the ultimate source of authority. During the century that followed the Gallic invasion they expressed this authority through the legislative, judicial and electoral activity of their assemblies, the Curiata, Centuriata and Tributa, and of the purely plebeian Concilium Plebis: but they could only take action on matters submitted to them by the presiding magistrate. The tendency was, however, in the direction of real democracy; but it was checked by the skill with which the nobles manipulated the tribunate and religion and by the rapid expansion of Roman arms which distracted attention from domestic affairs and increased the control of the Senate. But in theory the Comitia were sovereign.
In conformity with their custom and conservatism the Romans allowed the various Comitia to exist side by side; none was abolished, although their functions were more clearly differentiated as time passed. The Comitia Curiata continued to assent to private acts like adoption and bequests, but its chief function remained its right formally to confer imperium on consuls and praetors. This, however, became such a formality that thirty lictors and three augurs could form a quorum of the curiae. The three other assemblies, Centuriata, Tributa, and Concilium Plebis, all had the right to legislate by the year 287; before this date the Concilium Plebis only claimed the right without possessing it by law. The Comitia Tributa gradually superseded the Comitia Centuriata in many spheres; although it is not always easy to determine through which body a given bill was passed, the tribal assemblies, especially the Concilium Plebis, were becoming the main legislative organs, partly because the thirty-five tribes were easier to handle than 193 centuries, and partly because when the presiding officers, who were the regular magistrates, included an increasing number of plebeians, these would tend to lay their proposals before the newer assembly. So the influence of wealth and age, which prevailed in the Comitia Centuriata, gave place to the predominance of the smaller country landowners who formed the backbone of the tribes, in which every man, rich and poor alike, had an equal vote. Indeed, it may have been the growing importance of the middle classes to the state that led to the shift from the centuries to the tribes; and later the Comitia Centuriata itself was reformed to bring it more into line with the Tributa and to give greater weight to the small landowner (p. 168). But while most legislation was carried through the tribal assemblies, the Centuriata still legislated regarding the declaration of war, the signing of peace, and conferring plenary power on the censor. The electoral functions of the assemblies remained divided: the Centuriata elected consuls, praetors and censors, the Tributa curule aediles and quaestors, the Concilium Plebis tribunes and plebeian aediles. Jurisdiction likewise was divided. The Comitia Centuriata remained the court of appeal in capital cases, while the Tributa heard cases on appeal when the punishment was only a fine; it is possible that trials still took place before the separate Concilium Plebis.
In all branches of government the Roman people was supreme, but in all the Senate overshadowed them: ‘senatus populusque Romanus’ was not an idle phrase. The people, or more precisely all adult male citizens, comprised the electorate, but in practice their choice of candidates was limited to those who could fulfil the duties of office. In legislation they had ultimate authority, but the resolutions of the Senate had in effect the same validity as their laws; and in time the Senate and praetors took over much of the detailed legislation from the assemblies. Further, the senators often invited tribunes to discuss a measure with them, before presenting it to the tribes. Judicial affairs also gradually passed into the hands of the praetors and Senate, though the assemblies did not allow interference in certain cases, as has been seen. The executive was elected directly by the people, but it was to the Senate rather that the magistrates showed deference. Finally, the administration was in practice transferred by the people to the Senate which acted as a Cabinet in place of the unwieldy assemblies; and the people only elected the Senate in an indirect manner. Thus at the very time when the Lex Hortensia proclaimed the sovereign right of the Roman people and Rome was approaching a democracy, the pendulum swung back in favour of a more oligarchical form of government. This was partly due to the draining off to the colonies of many poorer citizens with the consequent increase in the influence of the remaining landholding nobility, and partly to the complication of business which forced the Senate and magistrates to take the initiative. Further, the average Roman was not much interested in politics. Elections generally meant merely a change in the executive magistrates, not in the policy of the state: the legislative assemblies and the Senate, which determined Rome’s policy, remained the same. As long as the government protected his interests the small farmer cared little about the form of that government. Some of the nobility might be inspired by abstract Greek theories of government, a tribune might be a progressive democrat or the tool of the conservatives, but while his daily life ran smoothly the average farmer or town worker worried less about who governed him than about the efficiency and justice of that government. Thus at the very moment that the theoretical powers of the Roman people were emphasized and a real democracy was within their grasp, they in fact succumbed more and more to the control of the senatorial oligarchy.