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Comparative Government Unit 1: Political systems, regimes and governments

Comparative government studies how states, regimes and governments differ, using the six AP countries: the UK, Mexico, Russia, Iran, China and Nigeria.

Covers: Methods of political analysis, states, nations and regimes, democracy and authoritarianism, legitimacy and stability, sources of power, federal and unitary systems

Study guide

Comparative politics compares political systems to find patterns. Political scientists use quantitative data (numbers like GDP or voter turnout) and qualitative evidence (descriptions and case studies). They look for correlation, when two things vary together, and causation, when one actually causes the other. Normative statements say what ought to be; empirical statements describe what is. The AP course focuses on six countries: the United Kingdom, Mexico, Russia, Iran, China and Nigeria.

A state is a political organization with sovereignty over a territory and population. A nation is a group of people with a shared identity, such as language, culture or history. A nation-state combines both. A regime is the set of fundamental rules and norms of a political system, which lasts longer than any one government (the specific people in power). Democratic regimes have competitive elections, rule of law and civil liberties; authoritarian regimes concentrate power and limit participation. Many states are hybrid regimes, or illiberal democracies, holding elections that aren't fully free or fair. Russia is often described this way. China is a one-party communist state, and Iran is a theocracy with some elected institutions.

Legitimacy is the belief that a government has the right to rule. Max Weber described three sources: traditional (custom, like monarchy), charismatic (a leader's personal appeal) and rational-legal (laws and procedures). Governments keep legitimacy through economic growth, nationalism, elections and delivering services, and lose it through corruption and poor performance. Stability depends on legitimacy and the ability to control territory. Power can be distributed in a unitary system, where the central government holds most power (the UK, China, Iran), or a federal system, where power is shared with regions (Mexico, Russia, Nigeria). Devolution transfers power to regional governments, as the UK did with Scotland, Wales and Northern Ireland.

Democratization is the shift from authoritarian rule toward democracy: competitive elections, peaceful transfers of power, protected civil liberties and the rule of law. A democracy is consolidated when all major groups accept elections as the only legitimate way to gain power. A key test is when a ruling party loses an election and steps down. Nigeria spent most of 1966-1999 under military rule before the Fourth Republic began in 1999. In 2015, opposition candidate Muhammadu Buhari (APC) defeated President Goodluck Jonathan (PDP), the first time an incumbent lost to the opposition at the ballot box. Stability is still threatened by Boko Haram and other insurgents in the northeast, banditry in the northwest, farmer-herder violence and separatist tension in the southeast.

A failed or fragile state cannot control its territory, provide basic services or keep order, often because of civil conflict, corruption or economic collapse. Measures like the Fragile States Index, Freedom House scores, the Corruption Perceptions Index and the Human Development Index let political scientists compare countries on these dimensions. China's Communist Party bases much of its legitimacy on rapid economic growth and rising living standards, along with nationalism. Since 2012, Xi Jinping's anti-corruption campaign, run by the Central Commission for Discipline Inspection and, since 2018, the National Supervisory Commission, has punished over a million officials. The campaign boosts public trust while also removing Xi's rivals.

Russia is often called a 'managed' or 'sovereign' democracy. Elections occur, but the Kremlin controls major media, removes serious challengers from the ballot and relies on loyal elites. Widespread corruption and the power of oligarchs tied to the state weaken public trust and the rule of law. Iran's 1979 revolution replaced the shah's monarchy with a theocracy based on rule by the Islamic jurist. After Supreme Leader Ali Khamenei was killed in a February 2026 airstrike, the Assembly of Experts named his son Mojtaba Khamenei as successor in March 2026. That quick, IRGC-backed choice raised questions about whether religious authority was being passed down like a hereditary title.

Key ideas

• The AP course compares the UK, Mexico, Russia, Iran, China and Nigeria.
• A state has sovereignty; a nation is a group with shared identity.
• Regimes are the lasting rules; governments are the people in power.
• Legitimacy can be traditional, charismatic or rational-legal.
• Unitary systems centralize power; federal systems share it with regions.

Formulas and rules

Common mistakes

• Confusing state (political unit) and nation (people with shared identity).
• Thinking every country with elections is a democracy; hybrid regimes hold unfair elections.

Words to know

Comparative politics

The study and comparison of political systems.

Quantitative data

Numerical evidence like GDP or turnout.

Qualitative data

Descriptive evidence like case studies.

Correlation

Two variables that change together.

Causation

One variable directly causing a change in another.

Empirical statement

A factual description of what is.

Normative statement

A judgment about what ought to be.

State

A political organization with sovereignty over territory and people.

Nation

A group of people with a shared identity.

Nation-state

A state whose people share a national identity.

Sovereignty

The ability to govern a territory without outside interference.

Regime

The fundamental rules and norms of a political system.

Government

The specific people and institutions currently in power.

Authoritarian regime

A system where power is concentrated and participation is limited.

Illiberal democracy

A regime with elections but limited civil liberties.

Legitimacy

The belief that a government has the right to rule.

Rational-legal legitimacy

Authority based on laws and procedures.

Unitary system

Most power held by the central government.

Federal system

Power shared between national and regional governments.

Devolution

Transfer of power from central to regional governments.

Sample practice questions

5 more questions like these, from level 1 to 5, are in the practice set.