The three branches and why they are separated
A political institution is a lasting set of rules and offices through which a country makes decisions: parliament, the cabinet, courts, the head of state, elections.
- Legislature (parliament, congress, assembly): elected representatives who make laws, approve the budget and watch the government.
- Executive: the head of government and ministers who run the country day to day.
- Judiciary: courts that settle disputes and check that laws follow the constitution.
Separation of powers means no single person or body holds all three jobs. Each branch can stop the others from going too far (checks and balances).
Representation
Citizens cannot all vote on every law, so they elect representatives. The electoral system decides how votes become seats: in first-past-the-post, the candidate with the most votes in each area wins; in proportional representation, parties get seats in line with their share of the vote. Proportional systems often produce coalition governments of several parties.
Comparing parliamentary, presidential and semi-presidential systems
Parliamentary system
Voters elect the legislature. The executive (Prime Minister and cabinet) comes from the legislature and must keep its confidence (majority support). The head of state (a monarch or an indirectly elected president) is mostly ceremonial. Examples: India, UK, Japan, Canada, Germany.
Presidential system
Voters elect the president and the legislature separately. The president is both head of state and head of government, has a fixed term and chooses ministers who are usually not members of the legislature. Examples: USA, Brazil, Mexico, Indonesia.
Semi-presidential system
A directly elected president shares power with a Prime Minister who is responsible to parliament. When the president's party lacks a majority, the president may have to appoint a PM from the opposition: this is called cohabitation. Examples: France, Portugal, Sri Lanka (mixed).
| Parliamentary | Presidential | Semi-presidential | |
|---|---|---|---|
| Who picks the head of government? | Parliament's majority | Voters | President picks PM; PM needs parliament |
| Fixed term? | No (can fall early) | Yes | President yes; PM no |
| Removal | No-confidence vote | Impeachment only | PM by no-confidence; president by impeachment |
| Strength | Fast law-making, clear responsibility | Stable, strong separation | Flexible |
| Weakness | Can be unstable with many parties | Gridlock if branches disagree | Conflict between president and PM |
Executive term limits
A term is the fixed period a leader serves before a new election. A term limit caps how many terms one person may serve. The US president may be elected at most twice (4-year terms). Many presidential countries allow only one or two terms.
Why have them? Leaders in office can use state power to win again and again. A limit forces a change at the top, gives new people a chance and protects democracy.
Arguments against: voters lose the right to re-elect a popular leader, and leaders in their last term may stop caring about voters (the "lame duck" problem).
Parliamentary systems usually have no limit on how long a PM serves, because parliament can remove the PM at any time and elections are held at least every 4 to 5 years. A warning sign in any country is a leader changing the constitution to remove the limit.
Removal of executives: no confidence and impeachment
Vote of no confidence (parliamentary): if more than half of the lower house votes that it no longer trusts the government, the PM and cabinet must resign or call an election. It is a political test; no crime is needed. Some countries (like Germany) use a constructive no-confidence vote: parliament must agree on a new PM at the same time.
Impeachment (presidential): a legal-political process for serious wrongdoing. Usually the lower house brings charges and the upper house holds a trial; a large majority (often two-thirds) is needed to remove the president. It is rare and hard by design, so a president cannot be removed just for being unpopular.
Other ways a leader leaves: losing an election, resigning, death or illness, and in some places a recall vote by citizens.
Independent legislatures and checks on the executive
A legislature is independent when the executive cannot control it: members are freely elected, it sets its own agenda, it cannot be shut down at will, and members can speak and vote without fear.
Tools a strong legislature uses:
- Law-making: it can amend or reject bills.
- The budget ("power of the purse"): no tax or spending without its approval.
- Questions and debates: ministers must answer in public (Question Hour in India).
- Committees: small groups of members examine bills and investigate departments.
- Approving appointments and treaties (in some systems).
In presidential systems the legislature is usually more independent, because the president cannot dissolve it. In parliamentary systems, a government with a large majority and strict party discipline can dominate parliament, so opposition rights and committees matter a lot. A bicameral legislature (two houses) adds a second check.
Try it: map your own country
Answer four questions about any country (your own or one in the news): 1) Do voters elect the head of government directly? 2) Can parliament remove that person without a crime? 3) Is there a term limit? 4) Can the executive dissolve the legislature? Then use the free-play step of the 3D model to check which system fits. Two "yes" answers to 2 and 4 usually mean parliamentary.
Key formulas and definitions
- Legislature = makes laws, approves budget, checks executive
- Executive = head of government + ministers who carry out laws
- Confidence = majority support of the lower house (needed by a PM)
- No-confidence vote = parliament removes the government by a simple majority
- Impeachment = charges + trial for serious wrongdoing; usually needs a two-thirds vote
- Term limit = maximum number of terms one person may serve
- Cohabitation = president and PM from opposing parties (semi-presidential)
- Separation of powers + checks and balances = no branch holds all power
Worked examples
1. In country X, voters elect a parliament of 300 seats. Party A wins 160 seats and its leader becomes head of government. Which system is this?
Parliamentary. The head of government comes from the majority in parliament (160 > 150), not from a separate vote.
2. In a parliament of 545 members, how many votes are needed to pass a no-confidence motion if all members vote?
More than half: 545 ÷ 2 = 272.5, so at least 273 votes.
3. A president wins an election in 2020 and again in 2024. The rule is two 4-year terms. When must a new person take office?
Term 1: 2020–2024, term 2: 2024–2028. The president cannot run again, so a new president takes office in 2028.
4. In a semi-presidential country, the president's party loses the parliamentary election. What usually happens?
The president appoints a Prime Minister from the new majority, because the PM needs parliament's confidence. President and PM come from opposing parties: cohabitation.
Common mistakes
- Thinking every country with a president is presidential. India has a president, but power lies with the PM and parliament, so India is parliamentary.
- Mixing up impeachment and no confidence. Impeachment is for serious wrongdoing and needs a big majority; no confidence is a simple political vote.
- Believing a presidential leader can dissolve congress. In a pure presidential system neither branch can end the other's term.
- Assuming term limits exist everywhere. Most parliamentary systems have no limit on how long a PM serves.