Unit 2: Political Institutions

Every country on the exam runs on a set of institutions, and those institutions decide who holds power, how power changes hands, and what limits power faces. This unit covers the executive, legislative, and judicial branches of the six course countries, and it is the largest unit on the exam.

2.1 Parliamentary, Presidential, and Semi-Presidential Systems

Start with the three models, because every executive on the exam is classified against them. In a parliamentary system, the executive is drawn from the legislature. The chief executive, usually called the prime minister, is the leader of the party or coalition that holds a legislative majority, and the government stays in power only as long as it keeps the legislature's confidence. There is no separately elected president, and the fates of the executive and the legislature are tied together.

In a presidential system, the president is elected separately from the legislature and serves a fixed term. The executive cannot be removed just because the legislature disagrees with it, and the legislature cannot be dissolved by the executive. Each branch has its own electoral mandate, which is the source of both the system's predictability and its tendency toward gridlock when different parties control different branches.

A semi-presidential system splits the executive in two. A directly elected president shares power with a prime minister, and the prime minister and cabinet are responsible to the legislature. The real balance of power depends on the country and on the moment. When the president's allies control the legislature, the president dominates. When the opposition controls it, the two executives can pull in different directions.

The classifications are straightforward for four of the six. The United Kingdom is parliamentary. Mexico and Nigeria are presidential. Russia is semi-presidential, with a directly elected president who dominates the prime minister in practice. Iran and China sit outside the three models. Iran is a theocratic republic where an unelected Supreme Leader holds ultimate authority above an elected president. China is a party-state where the CCP General Secretary is the most powerful position and no executive office is filled through competitive election.

2.2 Comparing the Three Systems

The three models differ in three ways the exam will ask you to compare: how the chief executive gets the job, how the executive relates to the legislature, and what keeps the system stable or breaks it.

2.3 Executive Systems

Now the six countries one by one. Learn the title, the selection method, and the term rules for each executive, because the exam tests all three.

Notice what the table hides: titles that sound alike but work differently. The prime minister of the United Kingdom and the prime minister of Russia are not the same job. In the UK the prime minister is the chief executive and answers to the Commons. In Russia the prime minister is appointed by the president, confirmed by the Duma, and subordinate to the president. Same title, different system.

2.4 Executive Term Limits

Term limits look like a small detail until you compare them across the six countries. Then they become one of the clearest windows into how each system handles power.

• Mexico: the strictest rule on the exam. One 6-year term, the sexenio, and no reelection ever. Article 83 of the 1917 constitution bars anyone who has held the office, even on a caretaker basis, from holding it again.
• Nigeria: 4-year terms with a maximum of two, which forces regular rotation at the top.
• Russia: the president serves 6-year terms, lengthened from 4 by a 2008 constitutional amendment, and the presidency is the dominant office in the system.
• China: the NPC removed presidential term limits from the constitution in 2018, so the presidency no longer has a constitutional cap.
• Iran: the president serves 4-year terms, with every candidate vetted by the Guardian Council. The Supreme Leader faces no term limit at all and serves for life.
• United Kingdom: no fixed term for the prime minister. The PM serves as long as the party holds its Commons majority and keeps its confidence, with elections due at least every five years.

Term limits matter for this course because they set the rhythm of accountability. A president who can never be reelected, as in Mexico, never faces voters again, which removes both electoral pressure and electoral accountability. A two-term cap, as in Nigeria, forces turnover. Removing limits, as China did in 2018, opens the door to indefinite rule. When an FRQ asks you to compare two countries, term rules are often the fastest way to show how their systems differ.

2.5 Removal of Executives

Every system has a way to remove its executive. The mechanism tells you where real accountability sits.

In the United Kingdom, the prime minister stays in office only with the confidence of the Commons majority. A government that loses that confidence falls, and a formal vote of no confidence is the mechanism that ends it. Losing the support of the legislature is itself the removal process.

In Mexico and Nigeria, presidents serve fixed terms, so the legislature cannot remove them over policy disagreements. The formal mechanism is impeachment, a legal process against a specific officeholder rather than a political judgment on the government. Fixed terms protect the executive from the legislature, which is exactly why impeachment exists as the exception.

Iran's Majles can question and dismiss cabinet ministers and can impeach the president, which gives the elected legislature a real removal power even inside a theocratic system. That power sits underneath the Supreme Leader's authority, but it is genuine against the president and the cabinet.

In Russia and China, formal removal rules exist, but removal through institutional channels is not how power actually changes hands. In Russia the president dominates a constrained legislature and a dependent judiciary, so the institutions that would have to act against the president answer to him. In China there is no competitive selection at all, so removal runs through the party hierarchy, not through voters or an independent legislature.

The pattern is worth stating plainly. In the democracies, removal is a legislative or electoral process with real teeth. In the authoritarian systems, the formal rules describe removal, but the power structure decides whether those rules can ever be used.

2.6 Legislative Systems

Legislatures vary more than any other institution on the exam. Learn the structure, the size, and how members get their seats.

Electoral systems shape who sits in these chambers. The UK and Nigeria use first-past-the-post, which rewards large parties. Mexico and Russia use mixed parallel systems that combine district winners with proportional seats. Iran uses a two-round system for the Majles. In China, where elections are not competitive, the NPC's composition reflects party decisions rather than voter choice.

2.7 Independent Legislatures

A legislature exists in every course country. The question is whether it can check the executive.

• United Kingdom: the Commons is a genuine check. The government needs its confidence, most real legislative power sits with the elected Commons rather than the unelected Lords, and a majority can end a premiership.
• Mexico: the Congress of the Union is separately elected with its own mandate, and real opposition parties sit in it. The PRI's loss of the presidency in 2000 ended decades of one-party dominance and made the legislature a functioning check.
• Nigeria: the National Assembly has the tools to check the president, including impeachment, though democratic deficits limit how far that checking power goes in practice.
• Iran: the Majles is elected and can question ministers, dismiss them, and impeach the president. But the Guardian Council can veto any Majles legislation for incompatibility with Sharia or the constitution, which caps the Majles' independence from above.
• Russia: the Duma legislates, but United Russia dominates it and genuine opposition is marginalized, so in practice it functions as an extension of presidential power rather than a check on it.
• China: the NPC is constitutionally the highest organ of state power, but in practice it ratifies decisions already made by the CCP.

Three things determine whether a legislature is independent: its own electoral mandate, real opposition sitting in its seats, and an executive that actually needs its approval. An elected chamber with no opposition, or one whose laws can be vetoed by an unelected council, is a legislature in form more than in function.

2.8 Judicial Systems

Judicial independence is the degree to which courts can decide cases without pressure from the executive. The six countries spread across the full range.

2.9 Independent Judiciaries

Two phrases capture what judicial independence is for. Under the rule of law, the law binds everyone, including the government: leaders can lose in court, and courts can strike down what the other branches do. Under rule by law, the law is a tool the government uses to control others without constraining itself: courts exist and hear cases, but they answer to the executive.

That is why judicial review matters. It is the mechanism that lets courts invalidate actions of the legislature or the executive, which is what turns constitutional limits into enforceable ones. Where independence is high, as in the UK, review is a real constraint. Where it is low, as in Russia, China, and Iran, constitutional promises have no court willing or able to enforce them.

Deep Dive: Iran's Institutions

Iran causes more lost points than any other country in this unit because it has three councils with similar names and jobs that blur together. Give each council one composition and one job, and the blur disappears.

The Guardian Council: the gatekeeper. Twelve members: six clerics appointed directly by the Supreme Leader, plus six jurists nominated by the head of the judiciary and approved by the Majles. It does three things: it can veto any Majles legislation for incompatibility with Sharia or the constitution, it vets all candidates for president, the Majles, and the Assembly of Experts, and it supervises elections. It guards the laws, the ballot, and the vote.

The Expediency Council: the tiebreaker. Created in the 1988 constitutional revision, it resolves legislative deadlocks between the Majles and the Guardian Council, and it advises the Supreme Leader. Its members are appointed by the Supreme Leader. When the Majles passes a bill and the Guardian Council vetoes it, this is the body that settles the dispute.

The Assembly of Experts: the body that picks the Leader. Eighty-eight clerics, popularly elected to 8-year terms. Its job is to select the Supreme Leader. It can theoretically dismiss him, though it never has.

Around those councils sit the offices students already know. The Supreme Leader holds lifetime tenure with ultimate authority over the military, the judiciary, and the media. The president serves 4-year terms and is popularly elected, but every candidate must pass Guardian Council vetting, and the president is subordinate to the Supreme Leader on security and foreign policy. The Majles has 290 members elected to 4-year terms in a two-round system, with five seats reserved for recognized religious minorities, and it can question and dismiss ministers and impeach the president. There are no formal Western-style parties; politics runs through factions, mainly principlists and reformists.

Confusions That Cost Points

Practice Questions

Original questions written for this guide in the style of the AP exam. Answers and explanations are on the next page, so complete the questions before checking them.

Answer Key

1. B. Russia is semi-presidential: a directly elected president serves alongside a prime minister, and the president dominates in practice. A is wrong because Russia's prime minister is appointed by the president, confirmed by the Duma, and subordinate to the president. C describes Mexico's sexenio, not Russia. D describes Iran's theocratic system.

2. A. Mexico's president serves one 6-year term, the sexenio, and Article 83 of the 1917 constitution bars reelection ever. B describes Nigeria's two-term cap. C describes Russia's 6-year presidential terms. D describes the parliamentary model, where the UK's prime minister needs the Commons' confidence.

3. C. The Guardian Council vets all candidates for president, the Majles, and the Assembly of Experts, and it can veto Majles legislation for incompatibility with Sharia or the constitution. A describes the Assembly of Experts, which selects the Supreme Leader. B describes the Expediency Council, which resolves deadlocks between the Majles and the Guardian Council, not the executive. D describes a power of the Supreme Leader, who appoints the head of the judiciary.

4. D. In the UK the monarch is the ceremonial head of state and the prime minister is the head of government. A reverses the two roles. B is wrong because China's president is head of state; the General Secretary holds the most power but it is a party office, not the head of state. C is wrong because Mexico's president is both head of state and head of government; the Senate president holds neither role.

5. A. Iran's Majles is unicameral, with 290 members. B is wrong: Mexico's Congress of the Union is bicameral, with a 500-member Chamber of Deputies and a 128-member Senate. C is wrong: Nigeria's National Assembly is bicameral, with a 360-member House of Representatives and a 109-member Senate. D is wrong: Russia's Federal Assembly is bicameral, with the 450-member State Duma and the Federation Council.

6. B. In a parliamentary system, a government that loses the legislature's confidence falls, and a vote of no confidence is the formal mechanism. A is wrong: Mexico's president serves a fixed sexenio and cannot be removed by Congress over policy disagreements. C is wrong: the Assembly of Experts selects the Supreme Leader and can theoretically dismiss him, but not through a vote of no confidence. D is wrong: the NPC ratifies CCP decisions in practice and does not dismiss the General Secretary.

7. C. The UK has high judicial independence, with courts able to check executive action. A is wrong: Russia's judiciary, including the Constitutional Court, has low independence from the executive. B is wrong: China's courts operate under CCP authority. D is wrong: Iran's judiciary has low independence, and the head of the judiciary is appointed by the Supreme Leader.

8. D. Mexico, Nigeria, and Russia are the three federal countries on the exam. A is wrong: the UK, China, and Iran are all unitary, and the UK's devolution does not make it federal. B is wrong because the UK is unitary. C is wrong because China is unitary.

One-Page Recall Check

Say each answer out loud before you look back, and mark the ones you cannot finish. Anything you cannot say out loud yet belongs in your flashcard deck. In Rycal, add those items to the Political Institutions deck and let spaced review bring them back over the next few days.

• Define parliamentary, presidential, and semi-presidential systems in one sentence each.
• Classify each of the six course countries and give the reason for each classification.
• Explain how the UK's prime minister gets the job and what keeps the prime minister in it.
• State the term rules for the chief executive in Mexico, Nigeria, Russia, China, and Iran, and note where the UK differs.
• Explain why term limits are a useful comparison point across countries.
• Contrast removal by vote of no confidence with removal by impeachment, and name a country for each.
• List each country's legislature, its chambers, and how members are chosen.
• Explain which legislatures genuinely check the executive and which function as rubber stamps, with reasons.
• Explain the difference between devolution and federalism, and say which applies to the UK.
• Name Iran's three councils, give the composition of each, and state its main job.
• Explain the difference between head of state and head of government, with two country examples.
• State the level of judicial independence in each country, and explain rule of law versus rule by law.

Key terms for this unit

Parliamentary system, Presidential system, Semi-presidential system, Vote of no confidence, Impeachment, Sexenio, Guardian Council, Expediency Council, Assembly of Experts, Supreme Leader, Majles, National People's Congress, State Duma, Federation Council, House of Commons, House of Lords, Devolution, Federalism, Head of state, Head of government, Judicial independence, Judicial review, Rule of law, Rule by law.

About this guide. Written for Rycal and aligned to the College Board AP Comparative Government and Politics course framework, Unit 2. All questions and explanations are original Rycal writing. Rycal is independent and is not affiliated with or endorsed by the College Board.