AP® Comparative Government and Politics review sheet from Aim for Five (aimforfive.com/comp-gov/units/2/2-1)
Unit 2 · Topic 2.1
2.1 Parliamentary, Presidential, and Semi-Presidential Systems
Countries organize their executive and legislature in three main ways. In a parliamentary system the prime minister comes from and answers to the legislature; in a presidential system voters choose the president separately; a semi-presidential system has both a president and a prime minister. Iran and China add their own twists.
Key terms
- parliamentary system
- presidential system
- semi-presidential system
- head of state
- head of government
- fusion of powers
Recent change to know (as of October 2026)
In July 2026 the UK's governing Labour Party chose a new leader, who became prime minister without a general election. That's how parliamentary systems work: the prime minister is whoever can command a majority in the House of Commons, so a party can change prime ministers between elections. The UK has done this several times, including in 2007, 2016, 2019 and twice in 2022.
Iran also has a new Supreme Leader, chosen in March 2026. Older videos and study guides may name past officeholders.
The three systems
- Parliamentary system: voters elect the legislature, and the leader of the majority party (or coalition) becomes prime minister. The prime minister and cabinet sit in the legislature and stay in office only while they keep its confidence. This joining of the executive and legislature is called fusion of powers.
- Presidential system: voters elect the president separately from the legislature, for a fixed term. The president is both head of state and head of government and can't be removed by a simple vote of no confidence. The cabinet answers mainly to the president, and the legislature can remove ministers only by impeachment. This is separation of powers.
- Semi-presidential system: a directly elected president shares executive power with a prime minister. The president nominates the prime minister, the legislature must approve, and the cabinet answers to both. The balance depends on the constitution and on politics.
Head of state vs. head of government
The head of state represents the country (ceremonies, greeting foreign leaders). The head of government runs the government day to day. In presidential systems one person does both; in the others the jobs are split.
| Country | System | Head of state | Head of government |
|---|---|---|---|
| UK | Parliamentary | Monarch (ceremonial) | Prime minister |
| Mexico | Presidential | President | President |
| Nigeria | Presidential | President | President |
| Russia | Semi-presidential | President (dominant) | Prime minister |
| Iran | Theocratic republic | Supreme Leader | President |
| China | Party-state | President (state post) | Premier; real power in the party leadership |
Iran and China don't fit the boxes
Iran has an elected president who runs the cabinet and the budget, but the Supreme Leader outranks the president and controls the armed forces, the judiciary and state media. The president's power is real but limited.
China's formal state looks like a mix of systems, with a president, a premier and a legislature. In practice the Chinese Communist Party makes the key decisions. The party's General Secretary is also state president and chairs the Central Military Commission, and the premier, who heads the State Council (the cabinet), is a member of the party's Politburo Standing Committee.
Worked examples
Try each one yourself first, then open the solution.
- Example 1
Applying the concept to a new case
In a country, the legislature votes no confidence in the cabinet, and the prime minister resigns. The directly elected president then appoints a new prime minister. Identify the type of system and explain.
Show the solutionHide the solution
- Step 1: Spot the parliamentary feature: the cabinet depends on the legislature's confidence.
- Step 2: Spot the presidential feature: there is also a directly elected president with the power to appoint the prime minister.
- Step 3: Both together mean power is shared between an elected president and a prime minister answerable to the legislature.
Answer: A semi-presidential system, because it combines a directly elected president with a prime minister who needs the legislature's confidence.
Common mistakes
- Saying UK voters elect the prime minister. Voters elect MPs; the prime minister is the leader who commands a Commons majority.
- Calling Russia presidential. It's semi-presidential on paper, though the president dominates in practice.
- Treating China's state president as the real source of power. The post matters because the party's General Secretary holds it.
On the exam
- Many multiple-choice questions give a short description and ask which system it is. Look for who chooses the head of government and whether the legislature can remove them.
- Know the head of state and head of government for all six countries; it comes up often.
Connected topics
Videos
Check yourself
4 questions on 2.1 Parliamentary, Presidential, and Semi-Presidential Systems. Pick an answer to see if you got it, and why.
In the United Kingdom, which official serves as head of state?
Which feature makes Russia's system semi-presidential rather than purely presidential?
In which course country is the chief executive both head of state and head of government?
In Country L, the prime minister leads the party with the most seats in the lower house of the legislature, and every cabinet minister is also a member of that house. After a scandal, a group of members from the governing party announces it will no longer support the government.
Opposition leaders immediately introduce a motion stating that the house has no confidence in the government. The prime minister responds that, if the motion passes, the country will hold a new election.
Hypothetical scenario
Which feature of Country L's system is shown by the fact that cabinet ministers are also members of the legislature?
0 of 4 answered