When the great war pitting the Athenians against the Peloponnesians first erupted, Pericles told his compatriots that, if they kept up their navy, focused on the conflict at hand, and refrained from wasting their resources on ulterior objects, they would "win through" - and Thucydides believed him. After Pericles' death, however, to the historian's dismay, the Athenians pursued risky adventures tangential to their struggle with the Spartans and their...