and council members may have been intended to prevent manipulations such as bribery, and to forestall the factional problems that could arise from the popularity contest that is an election. This was the Athenian answer to tyranny, but as events would show, this solution was incomplete at best. 
From the very establishment of the Athenian democracy there had been warning signs of a problem. Throughout the fifth century, for instance, the Assembly had become a forum for ostracism, a political mechanism by which a quorum of citizens could vote once a year to exile any man suspected of gathering too much personal power.20 Although ostracism was not used regularly -there was no reign of terror -it became a means to eliminate political rivals, and drained Athens of its most capable leaders. Those exiled included Miltiades, the hero of the Athenian victory over the Persians at Marathon, who was tried while gravely wounded; his son Cimon inherited his father's ruinous fine, defeated the Persians in 466, and was himself ostracized. Thucydides son of Melesias (not the historian), politically allied with Cimon, was ostracized by Pericles. The opponents of this group included men such as Xanthippus (father of Pericles) who prosecuted Miltiades and was himself exiled in 484; Pericles, who was not ostracized although he was fined; and the son of Pericles, who was later executed by the Assembly along with other generals after winning the sea battle at Arginusae in 406. Themistocles, who built and commanded the navy that beat the Persians in 480, was ostracized and fled to Persia. Thousands of pottery fragments, bearing the names of politicians facing ostracism, have been found by archaeologists in Athens. Hundreds had the name Themistocles written by a very few hands, which suggests that these ballots may have been distributed to the voters in order to rig the voting.
The closest we have to such theory is in Herodotus's Persian constitutional debate (The Histories 3.80f.); the Pseudo-Xenophonic Constitution of the Athenians, an antidemocratic pamphlet; and the funeral oration of Pericles as reconstructed in Thucydides, History 2.35f. Aristotle's Constitution does not treat the Assembly as an institution of government. To most Greek intellectuals, the Assembly easily became "the mob" (ochlos), which acted by popular opinion rather than reason; see, e.g., Thucydides, History 7.8 (see note 29 below). 
To usurp the democracy was a serious crime. See the oath of Demophantos, in Andocides 1. 
Aristotle, Constitution 22.1, attributes the ostracism law to Cleisthenes c. 508 b.c., but the first recorded ostracism, of Hipparchus, probably occurred in 487 b.c. According to Plutarch, Aristides 7, the last was Hyperbolus, killed in 411. Plato, Gorgias 516 d-e, sees ostracism as silencing undesired voices; only a few officials prevented the Assembly from throwing Miltiades into the pit. 
The Assembly could also audit officials by demanding an account of their actions when their term came to an end. This was an important way to control officials without infringing on an official's ability to conduct his office as he saw fit-but it became a forum for revenge. The citizens also maintained control over the military by electing generals to fixed terms. This, along with the threat of prosecution, prevented the growth of personal authority of the kind that brought civil war to Rome in the first century b.c.; no Athenian general ever marched on Athens to attempt a coup. But these generals were also at the mercy of the Assembly's whims, a situation that affected their ability to make proper decisions, and that could induce a climate of fear among the commanders.