A coalition government forms when no single party wins a legislative majority, so two or more parties combine their seats to reach one and share executive power, dividing cabinet posts among them. In AP Comp Gov, it's a hallmark of parliamentary systems (Topic 2.1).
A coalition government is what happens when an election produces no clear winner. In a parliamentary system, the head of government needs the support of a legislative majority to take and hold office. If one party wins more than half the seats, easy, it governs alone. If not, parties negotiate, combine their seats to cross the majority threshold, and split the executive between them. That usually means the largest party's leader becomes prime minister while smaller partners get cabinet ministries and policy concessions in exchange for their votes.
This matters because of how parliamentary systems work under PAU-3.A.1. Lawmaking and executive functions are fused, and the legislature can select and remove the head of government. So a coalition isn't just a one-time deal at election night. It has to hold together every day, because if a partner walks out, the government can lose its majority and collapse through a vote of no confidence. The UK usually avoids coalitions thanks to its single-member-district elections that manufacture majorities, but the 2010-2015 Conservative-Liberal Democrat coalition shows even Westminster isn't immune.
Coalition government lives in Unit 2: Political Institutions, specifically Topic 2.1, and supports learning objective 2.1.A, describing parliamentary, presidential, and semi-presidential systems. Here's the logic the exam wants you to see. Presidential systems like Mexico and Nigeria elect the executive separately for a fixed term (PAU-3.A.2), so a president doesn't need a legislative coalition to exist, only to pass laws. Parliamentary systems make the executive's survival depend on the legislature (PAU-3.A.1), which is exactly the condition that produces coalition governments. If you can explain why coalitions appear in one system and not the other, you've understood the deepest comparison in Unit 2. It also connects to electoral rules later in the course, since proportional representation tends to produce multiparty legislatures where coalitions are the norm.
Keep studying AP® Comparative Government Unit 2
Fusion of powers (Unit 2)
Fusion of powers is the reason coalitions exist. When the executive is chosen by and answerable to the legislature, a party without a majority literally cannot govern alone, so it has to buy partners with cabinet seats.
British prime minister (Unit 2)
The UK's first-past-the-post elections usually hand one party a majority, so the PM rarely needs a coalition. That's why the 2010 Conservative-Liberal Democrat coalition was such a big deal, and it makes the UK a great contrast case in comparison FRQs.
Cabinet (Unit 2)
Cabinet posts are the currency of coalition-building. Junior partners trade their legislative votes for ministries, which gives small parties real executive power they could never win on their own.
Semi-presidential systems and Russia (Unit 2)
In a semi-presidential system like Russia, a directly elected president coexists with a prime minister responsible to the legislature. When the president and parliamentary majority come from opposing forces, you get tension over who controls the government, a different problem than coalition bargaining but caused by the same question of where executive power comes from.
Coalition government shows up mostly in Unit 2 questions about regime structure. Multiple-choice stems test whether you know which system produces coalitions and why: expect contrasts with Mexico's presidential system (separate fixed-term elections, cabinet responsible to the president) and Russia's semi-presidential setup, where a president facing a hostile parliamentary majority creates gridlock rather than a negotiated coalition. The 2018 short-answer set used the term, and SAQs typically ask you to define it and explain a consequence, like policy compromise, smaller-party influence, or government instability if a partner defects. The verb that matters is explain. Don't just say parties team up; say they combine seats to reach a legislative majority, share cabinet positions, and risk collapse via a no-confidence vote if the coalition fractures.
Both describe an executive without unified legislative support, but they happen in different systems. Divided government occurs in presidential systems (like Mexico) when the separately elected president faces a legislature controlled by another party; both survive because they have fixed terms. A coalition government occurs in parliamentary systems, where the executive can't survive without a majority, so parties must formally join forces and share the cabinet. One is a standoff between separate branches; the other is a partnership inside one fused branch.
A coalition government forms when no party wins a legislative majority, so multiple parties combine their seats to reach one and share executive power.
Coalitions are a feature of parliamentary systems because the head of government needs majority legislative support to take office and stay in office (PAU-3.A.1).
Presidential systems like Mexico and Nigeria don't form coalition governments in the same way, because the president is elected separately for a fixed term and doesn't need a legislative majority to survive (PAU-3.A.2).
Coalition partners are paid in cabinet posts and policy concessions, which gives small parties outsized influence over policy-making.
Coalitions are fragile: if a partner withdraws, the government can lose its majority and fall through a vote of no confidence.
The UK's 2010-2015 Conservative-Liberal Democrat coalition is the go-to course example, notable precisely because UK elections usually produce single-party majorities.
It's a government formed when two or more parties combine their legislative seats to reach a majority and share executive power, typically splitting cabinet positions. It's tested in Topic 2.1 as a feature of parliamentary systems.
Not in the parliamentary sense. Mexico's president is elected separately for a fixed term and the cabinet answers to the president, so the executive doesn't need a coalition to hold office. A president without a legislative majority gets divided government and gridlock, not a shared cabinet.
A coalition government is a formal partnership inside a parliamentary executive, with parties sharing cabinet seats to hold a majority. Divided government is a presidential-system standoff where the president and legislature are controlled by different parties but each survives independently on fixed terms.
Usually not. The UK's single-member-district plurality elections tend to manufacture single-party majorities, so the prime minister rarely needs partners. The 2010-2015 Conservative-Liberal Democrat coalition was a rare exception worth citing as evidence.
Because they depend on every partner's votes to keep a legislative majority. If a junior party quits over a policy dispute, the government can lose a vote of no confidence, forcing a new government or new elections. That instability is a classic consequence to explain on an SAQ.
Connect this key term to the AP exam workflow: review the course, practice questions, and check related study tools.
Review units, study guides, and course resources.
Check this vocabulary in multiple-choice context.
Apply key concepts in written AP responses.
Estimate the exam score you are working toward.
Review the highest-yield facts before practice.
Put the full course together before test day.