A parliament is a national legislature that makes laws and, in parliamentary systems like the United Kingdom's, also produces the executive, since the prime minister and cabinet come from and stay accountable to the legislative majority. In AP Comp Gov, it's a core source of power and authority (Topic 1.5).
A parliament is a legislative body made up of representatives (usually elected, usually from competing political parties) that writes and passes laws. So far, that sounds like any legislature. What makes a parliament special in AP Comp Gov is the fusion of powers. In a parliamentary system, the executive isn't elected separately. The prime minister is the leader of the majority party or coalition in the legislature, and the cabinet is drawn from Parliament too. The executive survives only as long as it keeps the confidence of the legislative majority.
The course's go-to example is the United Kingdom's Parliament at Westminster. It's bicameral, with an elected House of Commons holding real power and an unelected House of Lords playing a mostly advisory role. Because the UK has no single written constitution, Parliament itself is the supreme source of legal authority (parliamentary sovereignty). That's exactly the point Topic 1.5 wants you to see. Legislatures are one of the listed sources of power and authority, and in the UK, Parliament is arguably the source.
Parliament lives in Unit 1: Political Systems, Regimes, and Governments, specifically Topic 1.5: Sources of and Changes in Power and Authority, supporting learning objective AP Comp Gov 1.5.A (explain sources of power and authority in political systems). The CED lists legislatures alongside constitutions, religions, militaries, parties, and popular support as sources of regime authority. Parliament is your cleanest example of a legislature playing that role. It also sets up the comparisons the whole course runs on. The UK's parliamentary sovereignty contrasts with China's authority flowing through the Communist Party, Iran's authority flowing through Sharia law and clerical institutions after the 1979 Revolution, and Russia's heavily executive-dominated 'managed democracy.' If you can explain where Parliament's authority comes from, you can explain what makes the UK different from the other five course countries.
Keep studying AP Comparative Government Unit 1
Legislative Branch (Unit 2)
Every course country has a legislature, but they don't all matter equally. The UK Parliament actually governs, while Russia's Duma mostly rubber-stamps the executive's agenda. Comparing how much real power each legislature holds is one of the most common comparison tasks in the course.
Bicameral (Unit 2)
The UK Parliament is bicameral, but lopsided. The elected House of Commons holds nearly all the power, while the House of Lords can delay but not block legislation. That asymmetry is a favorite exam detail because it shows that 'two chambers' doesn't automatically mean 'two equal chambers.'
Constitution (Unit 1)
The UK has no single written constitution, so Parliament fills that gap. Parliamentary sovereignty means no court can strike down an act of Parliament the way the US Supreme Court can strike down a law. Authority flows from the legislature itself, not from a higher constitutional document.
1979 Revolution (Unit 1)
Iran shows the contrast. After 1979, ultimate authority shifted to religious institutions and Sharia law, so Iran's elected parliament (the Majles) is checked by unelected clerical bodies like the Guardian Council. Same word, parliament, but a totally different position in the chain of authority.
Parliament shows up constantly in multiple-choice stems comparing sources of authority across countries, like questions asking how the source of political authority differs between the UK and Russia, or how devolution in the UK differs from federalism. Devolution questions are really Parliament questions in disguise, since Parliament granted power to Scottish and Welsh assemblies and legally retains the power to take it back. On free-response questions, Parliament appears in comparison and conceptual-analysis tasks about legislative-executive relations. The 2017 CAQ on cabinets, for example, rewards knowing that in a parliamentary system the cabinet sits inside the legislature and answers to it. The skill being tested is rarely 'define parliament.' It's 'explain how Parliament's role makes the UK's regime different from China's, Iran's, or Russia's.'
Both are legislatures, but the relationship to the executive is opposite. In a presidential system like Mexico's or Nigeria's, voters elect the president separately from the legislature, and the two branches check each other (separation of powers). In a parliamentary system, the legislature creates the executive. The prime minister leads because their party won the most seats, and Parliament can remove the government with a vote of no confidence. Fusion of powers versus separation of powers is the distinction the exam keeps coming back to.
A parliament is a legislature that, in parliamentary systems, also produces and sustains the executive, since the prime minister and cabinet come from the majority in the legislature.
The CED lists legislatures as one of the main sources of power and authority (Topic 1.5), and the UK Parliament is the course's central example.
Parliamentary sovereignty means the UK Parliament is the supreme legal authority, because the UK lacks a single written constitution that sits above it.
The UK Parliament is bicameral but unequal, with the elected House of Commons holding real power and the House of Lords playing a limited delaying role.
Devolution in the UK is not federalism, because Parliament granted power to regional assemblies and legally retains the right to take that power back.
Comparing Parliament's authority to China's party-based authority, Iran's religious authority, and Russia's executive-dominated system is exactly the kind of analysis Unit 1 questions reward.
It's a national legislature that makes laws, and in parliamentary systems like the UK's, it also selects and sustains the executive. The prime minister leads the majority party in Parliament. It's a key example of a legislature as a source of power and authority in Topic 1.5.
No. Congress operates under separation of powers, with a president elected independently. The UK Parliament operates under fusion of powers, meaning the prime minister and cabinet come from Parliament itself and can be removed by a vote of no confidence.
No, and that's the famous part. The UK has no single written constitution, so Parliament holds parliamentary sovereignty. No court can strike down an act of Parliament the way the US Supreme Court can strike down a federal law.
No. Under federalism, regional governments have constitutionally protected powers. Under UK devolution, Parliament granted powers to Scotland, Wales, and Northern Ireland and could, in theory, take them back, since Parliament remains sovereign. This contrast is a frequent multiple-choice question.
They have legislatures, but with far less real power. Iran's Majles is constrained by unelected clerical bodies like the Guardian Council, and Russia's Duma largely defers to the executive under managed democracy. The exam loves asking you to compare how much authority each legislature actually exercises.