NRO contributor Victor Davis Hanson is a senior fellow at the Hoover Institution. His latest book is The Savior Generals, published this spring by Bloomsbury Books.

In ancient Athens, popular courts of paid jurors helped institutionalize fairness. If a troublemaker like Socrates was thought to be a danger to the popular will, then he was put on trial for inane charges like “corrupting the youth” or “introducing new gods.”

Convicting gadflies would remind all Athenians of the dangers of questioning democratic majority sentiment. If Athenian families were angry that their sons had supposedly died unnecessarily in battle, then they might charge the generals with capital negligence — a warning to all commanders to watch their backs. As in the case of Socrates, a majority vote often led to conviction, and conviction to a death sentence, or at least ostracism or exile. The popular courts freelanced to ensure that “the people” would hold sway over the perceived powerful and elite.

For a couple of years in revolutionary France, a Tribunal Révolutionnaire tried royalists, clergy, the wealthy, and supposed counter-revolutionaries on trumped-up charges of crimes against the people. Their purpose was a more violent version of the Athenian idea that the courts should serve the public by targeting the prominent, influential, or wealthy.

We in the United States are in jeopardy of turning our own criminal-justice system into revolutionary tribunals — fanned by the popular media and public opinion and directed against so-called enemies of the people....