Ancient Athens birthed both democracy and its most penetrating critics. The fundamental contentious issue was whether average people had the ability to manage the state and determine its proper interests, policies, and goals. For the defenders of democracy like the philosopher Protagoras, the politikê technê—i.e. the skills and knowledge necessary for coexistence in a community—belongs to all men by nature. Otherwise, no community could even exist. It would degenerate into a Hobbesian war of all against all. For its critics like Aristophanes, Plato, and Thucydides, radical democracy empowered people who did not have the skills or virtues necessary for seeing beyond their immediate private interests and desires in order to choose policies that benefitted the state as a whole, both in the present and the future.
On the whole, the American Founders agreed with these critics of democracy. The founders rejected democracy for the same reason they rejected monarchy and oligarchy: given that, as Alexander Hamilton wrote, "men are ambitious, vindictive, and rapacious," these irrational appetites and passions inherent in human nature, when concentrated in one governing faction, would cause each to degenerate into oppression and disorder if left unchecked. Fearing this outcome, the founders created a republican mixed government like that of ancient Sparta or Rome as described in the work of the Greek historian Polybius. "The balance of a well-ordered government," John Adams wrote, "will alone be able to prevent that emulation [rivalry for power] from degenerating into dangerous ambition, irregular rivalries, destructive factions, wasting seditions, and bloody civil war." Thus the Constitution established a monarchical executive, an oligarchic Senate, and a democratic House of Representatives, each empowered to balance the other and forestall the inevitable decline into tyranny each alone would undergo if it possessed too much power.