The structure and powers of Congress | Edexcel A-Level Politics
Updated: 5 days ago
For Specification 9PL0
Edexcel A-Level Politics | Free Revision Notes
Estimated study time: 50–60 minutes
The structure and powers of Congress A-Level Politics revision topic introduces the US legislature and explains why power is divided between the House of Representatives and the Senate. You need to understand Congress's bicameral structure, its membership and election cycle, and the distinction between powers shared by both chambers and powers reserved to one chamber. This builds directly on the constitutional framework and prepares you to study congressional representation, legislation and oversight in greater depth. The specification identifies these areas explicitly in section 2.1.
Learning Objectives 🎯
By the end of this revision page, you should be able to:
Define Congress and explain its bicameral structure.
Describe the membership and election cycles of the House of Representatives and Senate.
Distinguish between exclusive and concurrent congressional powers.
Explain important powers granted to Congress by the US Constitution.
Analyse how the division of powers between the two chambers affects the exercise of congressional power.
Revision Notes 📚
The structure and powers of Congress A-Level Politics revision overview
The US Constitution creates Congress as the legislative branch of the federal government. Congress is therefore central to the separation of powers established by the Constitution.
Congress is bicameral, meaning that it consists of two separate chambers:
the House of Representatives
the Senate
This arrangement reflects the wider constitutional principles covered in checks and balances. Neither chamber can normally legislate independently of the other.
The Edexcel specification requires knowledge of the bicameral nature of Congress, its membership and election cycle, and the distribution of constitutional, exclusive and concurrent powers.
The House of Representatives and the Senate
Although both chambers form Congress, they have different structures.
Feature | House of Representatives | Senate |
Basis of representation | Congressional districts | States |
Membership | 435 voting representatives | 100 senators, two from each state |
Length of term | 2 years | 6 years |
Election cycle | All House seats are contested every two years | Terms are staggered, with approximately one-third contested every two years |
Electoral basis | Representatives are elected from individual districts | Senators are elected across their whole state |
Legislative status | Constitutionally important chamber | Constitutionally equal to the House in ordinary legislation |
The different terms create different political pressures. Representatives face election every two years, so they are frequently accountable to their district electorate. Senators have longer terms and a state-wide mandate.
These electoral consequences are explored further when studying congressional elections and incumbency.
The congressional election cycle
Congressional elections take place every two years.
A mid-term election is defined in the Edexcel specification as a congressional election held midway through a president's four-year term.
The election cycle therefore works alongside the presidential cycle:
presidential elections occur every four years
House elections occur every two years
Senate elections also occur every two years, but individual senators serve six-year terms
This means Congress can change politically during a president's period in office. The relationship between Congress and the presidency becomes especially important when studying congressional oversight.
Why is Congress bicameral?
Bicameralism divides legislative authority between two independently elected chambers.
This matters because neither chamber can simply make federal legislation alone. Both must participate in the legislative process, and legislation normally requires agreement between the House and Senate before proceeding to the president.
The arrangement therefore:
prevents legislative authority from being concentrated in one institution
provides two different forms of representation
allows each chamber to check the other
makes agreement between the chambers necessary for legislation
The Senate is not merely a revising chamber subordinate to the House. Edexcel mark schemes explicitly recognise that the Senate is constitutionally equal to the House of Representatives in legislation.
You will examine the practical consequences of this structure in the congressional legislative process.
Constitutional powers of Congress
The Constitution gives Congress specific powers. Powers that are explicitly stated in the Constitution are known as enumerated powers.
The Edexcel specification defines enumerated powers as powers stated explicitly in the Constitution and identifies Article I, Section 8 as containing a list of congressional powers.
Important areas of congressional authority include:
raising federal revenue through taxation
borrowing money
regulating commerce
controlling federal expenditure
providing for the armed forces
declaring war
making federal legislation within its constitutional authority
The Constitution therefore gives Congress substantial authority over both domestic government and important areas of foreign and defence policy.
However, not every congressional power belongs equally to both chambers.
Exclusive powers
An exclusive power is a power that the Constitution reserves to one chamber rather than allowing both chambers to exercise it.
Exclusive powers of the House of Representatives
Important House-specific powers include:
initiating revenue legislation
impeaching federal officials, including presidents and federal judges
The impeachment power means that the House decides whether formal charges should be brought. Impeachment itself does not automatically remove an office-holder.
Exclusive powers of the Senate
The Senate has particularly important exclusive powers.
It can:
confirm or reject important presidential appointments, including nominations to the Supreme Court
ratify treaties negotiated by the president
conduct impeachment trials after impeachment by the House
The supplied Edexcel material specifically identifies confirmation of presidential appointments and treaty ratification as exclusive Senate powers.
These powers give the Senate a particularly important role in checking presidential authority.
The Senate and appointments
The president nominates individuals for a number of senior positions, but important appointments require Senate confirmation.
This illustrates checks and balances. Appointment is therefore not simply a presidential power because another branch has a constitutionally defined role in the process.
The Senate can:
consider a presidential nominee
scrutinise the nomination
approve or reject the appointment
The significance of this power becomes especially clear when studying the relationship between Congress and the presidency.
The Senate and treaties
The Senate also possesses an exclusive role in treaty ratification.
A president may negotiate and sign a treaty, but formal ratification requires the support of two-thirds of the Senate.
This gives the Senate influence over foreign policy as well as domestic politics.
⚠️ Be precise here. The two-thirds requirement applies to particular constitutional procedures, such as treaty ratification. It is not the normal requirement for passing ordinary legislation.
Concurrent powers
Concurrent congressional powers are powers exercised by both the House and Senate.
The most important example is ordinary federal legislation.
Both chambers can:
consider proposed legislation
debate bills
propose amendments
vote on legislation
scrutinise legislation through committees
For a bill to complete its congressional passage, the House and Senate must agree on the legislation.
This constitutional equality is important. The larger House does not have a general right to override the Senate simply because it contains more members.
Overriding a presidential veto
Congress also shares the constitutional ability to override a presidential veto.
If the president vetoes legislation passed by Congress, the veto can be overridden by a two-thirds majority in both chambers.
This is another example of checks and balances:
Congress passes legislation.
The president may veto it.
Congress can potentially override that veto.
The supermajority requirement makes overriding a veto more demanding than passing ordinary legislation.
Proposing constitutional amendments
Both chambers also participate in the congressional route for proposing amendments to the Constitution.
A proposal requires the necessary supermajority in both chambers before moving to the state ratification stage.
This links directly to constitutional entrenchment. Congress has an important role in constitutional change, but it cannot amend the Constitution by ordinary legislation.
Exclusive and concurrent powers compared
Type of power | Meaning | Examples |
Exclusive House powers | Powers reserved to the House | Initiating revenue legislation; impeachment |
Exclusive Senate powers | Powers reserved to the Senate | Confirming appointments; ratifying treaties; conducting impeachment trials |
Concurrent powers | Powers requiring participation by both chambers | Passing legislation; overriding a presidential veto; proposing constitutional amendments |
A strong exam answer should not simply memorise this table. You should explain why the distinction matters.
For example, Senate control over appointments allows the chamber to constrain presidential power, whereas concurrent legislative powers mean neither chamber can normally dominate the law-making process.
Is one chamber more powerful?
The constitutional distribution of powers makes this more complicated than it first appears.
The Senate possesses several significant exclusive powers, particularly over:
appointments
treaties
impeachment trials
However, the House also has exclusive responsibilities and is constitutionally essential to ordinary legislation.
Therefore, it is better to distinguish between different kinds of power than simply state that one chamber is always stronger.
The question of whether Congress's constitutional powers remain significant and effective is developed further in debates about congressional effectiveness.
Why the structure matters for examinations
Questions about Congress may require you to move beyond description.
Instead of writing:
The Senate confirms appointments.
Develop the political significance:
Senate confirmation means an important presidential power depends upon approval from another branch, so the Senate can use an exclusive constitutional power to check executive authority.
That turns factual knowledge into analysis.
The same approach becomes essential when you later make a comparison with the UK Parliament. The lesson plan specifically identifies comparison of the powers, strengths and weaknesses of the legislative Houses as part of the comparative section.
Hints from the Examiner Reports 💡
Examiner hint: Do not claim that Congress needs a two-thirds majority to pass ordinary legislation. The 2023 examiner report identified this as a continuing misconception. Two-thirds majorities apply to particular procedures, not normal passage of legislation.
Examiner hint: When making US-UK comparisons, compare like with like. The strongest responses compared the same feature in each institution and then explained the political significance of the difference. Comparing unrelated powers limits AO2 analysis.
Examiner hint: Description alone is not enough. Simply saying that the Senate is elected or has treaty powers produces limited analysis. Explain what the feature means for legitimacy, accountability or political power.
Examiner hint: For 12-mark comparative questions, lengthy introductions and conclusions usually add little credit. The examiner report recommends focusing directly on developed comparative points instead. Comparative theories are required in Question 2, not automatically in every 12-mark question.
Examiner hint: Use accurate specialist vocabulary such as exclusive power, legislative power, constitutional power and electoral mandate rather than vague phrases such as saying that one chamber can simply "stop" another.
Common Mistakes ⚠️
Mistake: Saying ordinary legislation requires a two-thirds majority
Why this is incorrect: Ordinary legislation does not generally need a two-thirds majority in Congress. Supermajorities are required for particular constitutional procedures, including overriding a presidential veto and Senate treaty ratification.
How to improve: Always ask what process the question refers to. Separate ordinary legislation from supermajority procedures.
Mistake: Treating the Senate as subordinate to the House
Why this is incorrect: The two chambers are constitutionally equal in ordinary legislation. A bill normally requires agreement from both chambers.
How to improve: Think of the House and Senate as co-equal legislative chambers with different exclusive powers, not as a dominant lower chamber and weaker upper chamber.
Mistake: Confusing exclusive and concurrent powers
Why this is incorrect: Senate confirmation of presidential appointments is not a power shared with the House. Likewise, ordinary legislation is not a Senate-exclusive power.
How to improve: Use a three-column revision table: House only, Senate only, both chambers.
Mistake: Mixing up the election cycles
Why this is incorrect: Members of the House serve two-year terms, whereas senators serve six-year terms.
How to improve: Remember: House = short cycle, Senate = long cycle. Connect this to the different representational pressures on each chamber.
Mistake: Listing a constitutional power without explaining its significance
Why this is incorrect: An extended answer needs analysis as well as factual knowledge.
How to improve: After naming every power, add: "This matters because..." For example, Senate confirmation matters because it allows Congress to check presidential appointments.
Exam-Style Questions ✍️
Question 1
What is meant by a bicameral legislature? (1 mark)
reveal mark scheme and indicative content
Answer: A legislature made up of two chambers.
Question 2
State the length of a term for:
a) a member of the House of Representatives
b) a senator. (2 marks)
reveal mark scheme and indicative content
Answer:
House of Representatives: 2 years
Senate: 6 years
Award 1 mark for each correct answer.
Question 3
Explain two differences between the election cycles of the House of Representatives and the Senate. (4 marks)
reveal mark scheme and indicative content
Indicative mark scheme:
Award up to 2 marks for each developed difference.
Relevant points include:
House members serve two-year terms, whereas senators serve six-year terms.
All House seats are contested on the two-year cycle, whereas Senate terms are staggered and only approximately one-third are contested at each two-year election.
The shorter House cycle creates more frequent electoral accountability than the Senate cycle.
Question 4
Explain one exclusive power of the House of Representatives and one exclusive power of the Senate. (4 marks)
reveal mark scheme and indicative content
Indicative mark scheme:
House examples:
impeachment
initiating revenue legislation
Senate examples:
confirming presidential appointments
ratifying treaties
conducting impeachment trials
For full marks, each power should be accurately explained rather than merely identified.
Question 5
A president has negotiated a new international treaty and nominated a new Supreme Court justice.
Explain how Congress can exercise constitutional power over these two presidential actions. (6 marks)
reveal mark scheme and indicative content
Indicative mark scheme:
The Senate has the exclusive constitutional role in treaty ratification.
Treaty ratification requires a two-thirds Senate majority.
The Senate also considers presidential nominations to important offices.
It can confirm or reject a Supreme Court nominee.
These powers demonstrate checks and balances because presidential actions in these areas depend upon legislative approval.
Question 6
Explain why the House of Representatives and Senate can be described as constitutionally equal in the legislative process. (6 marks)
reveal mark scheme and indicative content
Indicative mark scheme:
Relevant points include:
Both chambers participate in passing federal legislation.
Members in both chambers can debate and vote on bills.
Both chambers can consider amendments.
Legislation normally has to secure agreement from both chambers.
The House cannot simply override the Senate in ordinary legislation.
This gives bicameralism an important checking function within Congress.
Question 7
Analyse how the bicameral structure of Congress affects the exercise of congressional power. (12 marks)
reveal mark scheme and indicative content
Indicative mark scheme:
Strong responses could develop three themes:
Shared legislative authority
House and Senate must agree legislation.
This prevents either chamber from exercising legislative power alone.
Bicameralism therefore creates an internal check within Congress.
Different electoral structures
House members represent districts and serve two-year terms.
Senators represent states and serve six-year terms.
Their different electoral bases may lead the chambers to approach political decisions differently.
Exclusive constitutional powers
Senate confirmation and treaty powers give it influence over executive appointments and foreign affairs.
House-specific powers include impeachment and revenue legislation.
Bicameralism therefore divides different types of constitutional authority between the chambers.
Higher-level responses should develop logical chains of reasoning rather than simply listing structural features.
Question 8
Evaluate the view that the Senate is more powerful than the House of Representatives.You must consider this view and the alternative to this view in a balanced way. (30 marks)
reveal mark scheme and indicative content
Indicative mark scheme:
Arguments supporting the view could include:
The Senate has significant exclusive powers over presidential appointments.
It has the exclusive power to ratify treaties.
It conducts impeachment trials.
Senators have longer six-year terms, potentially giving them greater independence from immediate electoral pressure.
Arguments challenging the view could include:
The two chambers are constitutionally equal in ordinary legislation.
Legislation cannot normally become law solely because the Senate supports it.
The House possesses its own exclusive constitutional powers, including impeachment and the initiation of revenue legislation.
Both chambers participate in major concurrent powers such as veto overrides and constitutional amendment proposals.
Judgement:
A strong conclusion should distinguish different types of congressional power. The Senate possesses especially significant exclusive powers, but this does not make the House constitutionally subordinate because both chambers remain essential to ordinary federal law-making.
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