Why did Greek democracy fail?

The end of Athenian democracy is often described as a 'failure,' but this framing is misleading. Democracy in Athens lasted nearly two centuries (508–322 BCE) — longer than many modern democracies have existed. It ended not because of an internal collapse but because Athens was conquered by the Macedonian kingdom, whose military power no Greek city-state could match.

That said, Athenian democracy did face significant internal challenges. The system was vulnerable to demagogues — skilled orators who could sway the assembly through emotional appeals rather than sound reasoning. The decision to launch the Sicilian Expedition in 415 BCE — a massive military venture urged by the charismatic Alcibiades — ended in catastrophic defeat and the loss of most of Athens' fleet and fighting force.

The Peloponnesian War (431–404 BCE) exposed democracy's limitations in wartime. Athens' defeat by Sparta led to a brief oligarchic coup (the Thirty Tyrants) and, after democracy was restored, to the trial and execution of Socrates — an episode that troubled democratic legitimacy for centuries. Plato, Socrates' student, became one of democracy's most influential critics, arguing that governance required expert knowledge that ordinary citizens lacked.

The deeper structural problem was that Greek city-states were too small and too fractious to resist larger, centralized powers. Philip II of Macedon exploited Greek divisions, defeating the combined forces of Athens and Thebes at Chaeronea in 338 BCE. After Alexander's death, Macedonian control over Greece tightened, and democratic institutions were gradually curtailed. By 322 BCE, Athenian democracy was effectively over — ended not by the people's inability to govern themselves, but by the reality that small democratic communities are vulnerable to large autocratic ones.