The word republic comes from the Latin res publica, which means thing of the people. A republic is a political system without a monarchy; one where the people and their representatives rule. The first republic of note, created in Athens by Solon in 594 B.C, lasted nearly one hundred years before it collapsed. The Greeks were not kin to Republics, however, and preferred democracy as a political system.
Rome created its Republic when the last Etruscan king was expelled in 509 B.C. The king had relied on a group of men to advise him, called patres (fathers) -- later designated as the social class called Patrician. As the Republic began, the Fathers became the Senate, a people’s assembly was continued, and a pair of executive magistrates were created (Consuls). This system was weighted toward the aristocracy because the consuls were nominated by the Senate and were also in control of the judicial system.
Republicans loathe monarchies, so they build checks and balances to protect the people against an accumulation of power. In Rome, the consuls were given veto rights over each other, and served for one year. Moreover, a consul could only serve one term during his career. The Senate was given authority to suggest laws, but new laws had to be passed by the people’s assemblies. Eventually the Republic ended up with a complicated group of assemblies: one by tribe, one by district, one by wealth, and one for the Plebian class. Even with safeguards built into the Roman system, its success depended on factors beyond checks and balances: wise governance by the Senate, extension of rights to the people, and economic opportunity. Ultimately, the Roman Republic failed because the Senate began to work for its own interests rather than the interests of the people. A weakened Senate coupled with the advent of a professional army became the formula for creating a tyrant.
After Rome, republics were tried on several occasions; one of the most interesting being that of thirteenth century Florence. At the beginning of that period, the city was ruled by two factions, the Guelfs and the Ghibellines, each with its own government apparatus. Because the factions couldn’t agree on government policy, an arbiter’s office, called podesta, was created. Soon the arbiter had his own administration. As time went on, the Florentine government expanded in ridiculous fashion as hundreds of new governmental offices were created to address new problems. Terms of office had to be shortened to as little as two months to accommodate all the elections. For two hundred years, the checks and balances of this complex republic resisted attempts to destroy it, until the Medici family took control by sitting on the sidelines while their backers were elected to the majority of offices.
The founding fathers of the United States wanted to create a Republic in the style of Rome, because they too hated monarchies and sought to create a system under the control of the people. The problem was how to balance the branches of government. The states were a differentiating factor in the design, because they possessed power they were not interested in giving up. One of the plans introduced at the Constitutional Convention involved eliminating the states, but resistance to that concept was absolute. In the end, our government became a federal system with powers shared by the states and the national government.