In the last three months, we've been reduced to something like the ancient Athenian mob — with opportunistic politicians sometimes inciting, sometimes catering to an already angry public. The Greek comic playwright Aristophanes once described how screaming politicians — posing as men of the people — would sway Athenian citizens by offering them all sort of perks and goodies that the government had no idea how to pay for. The historian Thucydides offers even more frightening accounts of bloodthirsty voters after they were aroused by demagogues ("leaders or drivers of the people"). One day in a bloodthirsty rage, voters demanded...