Norman Rockwell’s 1943 painting “Freedom of Speech” is a visual encomium to the wonders of the democratic process. At the town meeting, everyone gets a chance to speak his or her mind. The blue-collar worker who has risen to say what he thinks of the proposal under consideration is free to say what he wants, and the other people listen to him respectfully.

We don’t know whether he will persuade others, but he has the chance to do so, and everyone seems to understand that his arguments are to be considered, to be given equal weight. Perhaps someone will rise to support him—or not. Perhaps someone will rise to argue against him.

Each will then cast a vote, having heard opposing points of view and weighed the pros and cons, and the majority’s decision prevails.

This sounds like an effective way to make decisions in a way that allows diverse viewpoint to be considered. After all, maybe the fellow in the blue shirt has some good ideas, a perspective others hadn’t thought of. Isn’t this how they did things back in ancient Athens? Happily, we have some first-hand accounts of Athenian democracy in action.

Thucydides, in his account of the Peloponnesian War, relates the response of the Athenian assembly to the Mytilenean Revolt. After persuasion by Cleon, the assembly votes to dispatch a ship with orders to execute every male Mytilenean. The very next day, after persuasion by Diodotus, the assembly decided that this was a bad idea, and that they should only execute a handful of Mytileneans. So they had to dispatch a second ship, rowing double-time, with orders to abort the mission of the first ship.

Plato, in his account of the trial of Socrates, relates how Meletus and Anytus were able to persuade the assembly that Socrates was an atheist and a sufficiently corrupting influence on the youth of Athens that he ought to be put to death. Despite Socrates’ attempts to demonstrate the absurdity of the charges, just over half the assembly comes to the conclusion that Meletus and Anytus are right. Socrates is duly put to death.

We can tell different stories about the circumstances where democratic deliberation takes place.  In the Rockwell painting, the story that is conveyed is one that shows the best democracy can be. The story of the execution of Socrates is not. People can be persuaded wrongly. Plato invites us to consider a deeper problem with democratic voting—he notes that the larger the group, the more likely the people are to feel uneasy at the vicissitudes of democratic processes. This leads them to invest a strong leader with greater power, in order to rule “effectively,” in a way that avoids messy disagreements and reversals. This person—the tyrant—now can rule free from any constraints, since his power “derives from” the people’s mandate. Plato’s analysis has been borne out many times since—Caesar, Robespierre, Napoleon, Hitler.

Perhaps you were wondering whether I’d round out that list with one or more American presidents. Perhaps you were waiting for me to add America’s new president-elect, Donald Trump. The good news is, modern constitutional republics such as the United States are designed with just this problem in mind, and have built-in countervailing structures, so that tyrannical inclinations are checked.

The bad news, however, is that these systems still depend on democratic voting. The Athenians realized, almost too late, that massacring the Mytileneans would do more harm than good, and that they had let their passions be wrongly swayed. When we vote for leaders who will stifle trade and curtail liberties, we are also allowing our passions to be manipulated. For democratic systems to work, we need to engage each other as if we were talking to the man in the blue shirt—calmly and respectfully considering different positions—not letting slick oratory whip us into a frenzy.