Harvard Law school professors Adriaan Lanni and Adrian Vermeule discuss sortition among other Athenian political mechanisms. They write:
In the ancient Greek world, selection of magistrates by lot was nearly synonymous with democracy. One of the most important functions of the lot in the Athenian democratic structure was to prevent any individual magistrate from amassing too much power and thereby threatening the sovereignty of the popular Assembly. We argue that the lot, taken together with the principles of rotation and collegiality, operated as precautionary measures against individuals gaining too much influence.
Although ancient sources do not provide a clear statement of the reasons for adopting the lot, selection by lot is uniformly associated with democratic reforms, as opposed to election, which is considered aristocratic. Selection by lot and the related concept of rotation in office likely had many purposes, including promoting popular and equal participation in government, reducing the risk of bribery and corruption, and minimizing factionalism and conflict between elite groups. But an equally important rationale for the lot and rotation was precautionary: as several scholars have pointed out, it prevented any individual executive official from gaining too much power, thereby insuring the sovereignty and supremacy of the Assembly. Hansen has pointed out that it was the critics of democracy who traced the lot to democratic notions of equality; both the famous statement of democratic principles in Herodotus’ Persian Debate and book 6 of Aristotle’s Politics appear to link the lot and limitations of magistrates’ power with preserving the sovereignty of the demos. Headlam similarly describes the distinctly second-best nature of the lot: “it was introduced . . . to prevent the executive officials from being too influential. . . .
[m]ediocrity was its object, because this was the only means of insuring that not only the name but also the reality of power should be with the Assembly.” It is important to emphasize that we are not arguing that the only, or even the chief, motivation for the introduction of the lot and rotation was the desire to limit magistrates’ power; we are simply highlighting this precautionary function of the lot as one of the many rationales for this institution.