in Sparta speech could never become the political tool it was elsewhere... In place of Peitho, the force of persuasion, as an instrument of the law, the Lacedaemonians extolled the power of Phobos, that fear which made all citizens bow in obedience.
Vernant argues that Sparta's subordination of persuasion to fear made it constitutionally incapable of completing the Greek transition to rational, democratic political order.
, The Origins of Greek Thought, 1982thesis