“A person is smart. People are dumb, panicky dangerous animals.”
So Kay declares in Men in Black, using this to justify keeping the public in the dark about the existence of aliens. This is a memorable scene, but, despite ongoing debates about government secrets and a contentious presidential election, not to mention elections in Europe, that raised questions about mass participation in politics and how decisions are made, it is something of an outlier in modern discussion about democracy.
The same is not true in ancient Greece. In Athens during the 5th century BCE one of they key questions was about the fickleness of the crowds and how dangerous this could be. When a leader was both respected and responsible, such as Thucydides credits to Pericles, the system worked, but there were repeated concerns about the masses being bought by crafty politicians. (Cleon is the usual target of accusation, but Plato says something similar about Pericles in his Gorgias.) I wrote about how Aristophanes describes this problem in Clouds where he stages a debate between Just and Unjust Logos, the unjust argument declaring that his brand of speaking works better in front of a crowd. This performance, though, appears to be a reflecting an Athenian aphorism about democracy.
From Herodotus (5.97):
It seems easier to mislead the many than the one, since Cleomenes of Lacedaemon alone was not deceived, but [Aristagoras] did this to to thirty thousand Athenians.
πολλοὺς γὰρ οἶκε εἶναι εὐπετέστερον διαβάλλειν ἢν ἕνα, εἰ Κλεομένεα μὲν τὸν Λακεδαιμόνιον μοῦνον οὐκ οἷός τε ἐγενετο διαβάλλειν, τρεῖς δὲ μυριάδας Ἀθηναίων ἐποίησε τοῦτο.
The year was 500/499 and Aristagoras, tyrant of Miletus, travelled to both Sparta and Athens looking for support for the rebellion against Persia he was trying to orchestrate (the Ionian Revolt). Cleomenes, the king of Sparta, effectively told Aristagoras to pound sand. There were a multitude of reasons why Cleomenes might have done this that had nothing to do with the failure of Aristagoras to dupe him, but Herodotus pairs the failure in Sparta with the vulnerability of democracy.