Early in its history, the republic was controlled by an aristocracy of individuals who could trace their ancestry back to the early history of the kingdom. Over time, the laws that allowed these individuals to dominate the government were repealed, and the result was the emergence of a new aristocracy which depended on the structure of society, rather than the law, to maintain its dominance. Thus, only a revolution could overthrow this new aristocracy.

It was the People of Rome - and thus the assemblies - who had the final say regarding the election of magistrates,[8] the enactment of new laws,[9] the carrying out of capital punishment, the declaration of war and peace, and the creation (or dissolution) of alliances.[8] There were two types of legislative assemblies. The first was the comitia ("committees"),[10] which were assemblies of all citizens. The second was the concilia ("councils"), which were assemblies of specific groups of citizens.[11]

The assembly of the tribes, the Comitia Tributa, was presided over by a consul,[12] and was composed of thirty-five tribes. The tribes were not ethnic or kinship groups, but rather geographical subdivisions.[15] The order that the thirty-five tribes would vote in was selected randomly by lot.[16] Once a measure received support from a majority of the tribes, the voting would end. While it did not pass many laws, the Comitia Tributa did elect quaestors, curule aediles, and military tribunes.