Charias and three accomplices a century later, c. 300 b.c. Xenophon claims that a graphe paranomon challenge was raised, but that voices in the Assembly threatened to try anyone who challenged the charges along with the generals. A voice rose from the back of the crowd: "it is monstrous if the people cannot do whatever they wish." The right to challenge a proposal legally was not officially repealed; it was simply shouted down, by a mob that accepted no limits to its power. Xenophon wrote that the citizens later regretted their actions, and shunned one of the prosecutors, who starved to death-an instance of the Assembly acting irresponsibly and then denying its own responsibility.
After two contentious meetings of the Assembly, in which opposing voices could not prevail, the six generals, including Pericles' son, were condemned and executed. With the best of her commanders destroyed, no ships left, and her treasury bankrupt, Athens was at the end of her resources. Within two years she starved and surrendered. 
3. The Deeper Cause of the Crisis The political context for the crisis in Athens had been established decades earlier, with the assertion of unlimited authority by the assembled citizens over long-standing aristocratic institutions and standards. But the intellectual cause was rooted in a certain attitude toward ideas, expressed in rhetorical arguments in which ethical and political concepts were disconnected from fixed principles. Nomos -a singular noun meaning the customs and norms of Athens as well as its laws -was increasingly seen 
as a set of human conventions, with no basis in reality other than that which human beings asserted. In these terms, the decisions of the Assembly established what was proper -and those decisions were the product of rhetoric, the art of public speaking for persuasive purposes. 
During the war with Sparta, rhetoric was studied and taught in Athens by a loosely connected group of thinkers known to us as the sophists. The sophists were united not by a single content to their teachings -there is no "sophistic" school of philosophy -but rather by a common concern for rhetoric, and by a willingness to teach for a fee. At the foundation of their thought they rejected absolute principles of morality and politics, and accepted that all principles were relative to a particular situation, malleable by the skillful use of language, and dependent on the particulars of the moment. A successful argument was not a true one that proved a case logically, but rather one that used words in a crafty way to create an image of reality, in order to induce an audience to make the desired decision. 
The triumph of the demagogues during the war with Sparta and the resulting actions of the Assembly were contemporaneous with the rise of rhetoric as an art in Athens. The sophist Protagoras of Abdera was likely in Athens by 443 b.c.; and by 427 b.c. rhetorical teaching had been imported from Sicily, by Gorgias and perhaps by Thrasymachus of Chalcedon.39 In the political speeches recreated in the History of Thucydides, in the surviving fragments of fifth-century forensic oratory, and in the scraps of rhetorical handbooks, we find the idea that right and wrong have no fixed meaning, but can be understood only in terms of probabilities, determined by the expediency of the moment. Antiphon's Tetralogies -twelve speeches, arranged in three groups of four -are rhetorical exercises that argued opposite sides of the same case, in terms of probabilities rather than truth.