Nearly every person alive lives under some government. Yet governments differ enormously. Some are chosen by voters and can be thrown out peacefully; some are run by kings, generals, clerics or a single party; some leave citizens largely free, others try to control every part of life. This course is a guided tour of those differences: how political scientists sort governments into types, how each type works, what its defenders say for it, and what the evidence shows about how each treats the people living under it.

State, government, regime

Three words are often confused. A state is the permanent political organization that controls a territory, such as France or Japan. The sociologist Max Weber defined it as a community that successfully claims a monopoly on the legitimate use of force within a territory. A government is the particular group of people running the state at a given time, which may change after an election. A regime is the basic set of rules about how power is gained and used: whether leaders are elected or inherit power, whether there are courts that can check them, which freedoms exist. Governments come and go within a regime; a change of regime, such as a revolution or a coup, changes the rules themselves. This course is mainly about regimes.

Aristotle's six

The oldest surviving system of classification comes from Aristotle, who, with his students, studied the constitutions of over a hundred Greek cities. In his Politics, he asked two questions: who rules, one, few or many, and in whose interest, the common good or the rulers' own. That gave six types.

• Rule by one for the common good is kingship; for the ruler's own interest, tyranny.
• Rule by a few for the common good is aristocracy, rule of the best; for their own interest, oligarchy, usually rule of the rich.
• Rule by the many for the common good Aristotle called polity; for their own interest, democracy, which for him meant rule by the poor majority in its own interest.

Aristotle thought the best practical constitution was a mixture, with a strong middle class. The Greek historian Polybius later argued that pure forms decay one into another in a cycle, and that Rome's stability came from its mixed constitution, combining consuls, a senate and popular assemblies.

Montesquieu's three

In The Spirit of the Laws (1748), the French philosopher Montesquieu proposed a different scheme: republics, run by the people or part of them, which depend on civic virtue; monarchies, ruled by one person under fixed laws, which depend on honor; and despotisms, ruled by one person without laws, which depend on fear. He also argued that liberty requires the separation of legislative, executive and judicial power, an idea that shaped many modern constitutions.

Weber's three kinds of legitimacy

Why do people obey? Weber identified three sources of legitimacy, the belief that a ruler has the right to rule. Traditional authority rests on custom, as with hereditary kings. Charismatic authority rests on devotion to an extraordinary individual, such as a revolutionary leader or prophet. Legal-rational authority rests on rules and offices, as when citizens obey a prime minister because she holds an office won under the constitution, not because of who she is. Most real governments mix all three.

Modern classifications

Political scientists today usually begin with one big division: democracies, where leaders are chosen in free and fair competitive elections and citizens enjoy basic freedoms, and autocracies, where they are not. Within each are many subtypes, and between them lie hybrid regimes with elements of both. Researchers rate countries using measures such as the Freedom House index and the V-Dem (Varieties of Democracy) project, which Level 8 examines.

Worked example: classifying a regime

Imagine a country where a president has ruled for twenty years. Elections are held every five years, and opposition parties exist, but the main opposition leader is in prison, most television stations are owned by the president's allies, and the courts never rule against the government. How should we classify it?

• Who rules? In practice, one person and his circle.
• How is power gained? Through elections, but elections that are not fair, because competitors are jailed and media are controlled.
• Is power checked? Not effectively. Courts and press are captured.
• In whose interest? We would need evidence on corruption and policy, but the lack of checks makes self-serving rule likely.

Despite its elections, most political scientists would call this an electoral autocracy or competitive authoritarian regime, not a democracy. The example shows why classification matters. Labels such as “republic” or “democracy” in a country's official name tell us little. What matters is how power actually works, and whether ordinary people can hold it to account.