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Reading Time: 8 min
Last Updated: August 26, 2026
Main Ideas: 5
Reading Time: 8 min
Last Updated: August 26, 2026
Main Ideas: 5

Topic 2.1 Notes – Congress: The Senate and the House of Representatives

Verified for 2027 AP® U.S. Government & Politics Exam
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Congress is the legislative branch created by Article I, and this topic is about why Congress has two chambers and how those chambers work differently. The House and Senate were built to represent different things, use different rules, and share power in a way that shapes how laws get made.

Bicameralism and Republican Representation

Congress is bicameral, which means it has two chambers, the House of Representatives and the Senate. For a bill to become law, both must pass the same version.

This setup comes from republicanism. In U.S. government, people usually do not make national policy directly. They govern indirectly through elected representatives who debate and vote for them.

The two chambers reflect two kinds of representation:

  • House represents the people, so seats are based on population.
  • Senate represents the states, so every state gets 2 senators.

That split came from the Great Compromise at the Constitutional Convention. Large states wanted population-based representation. Small states wanted equal representation. The compromise gave the country both.

Study guide illustration

The Great Compromise

This is why Congress has one chamber based on population and one that gives every state equal representation. It also makes lawmaking slower and more deliberate. A temporary majority in one chamber cannot act alone. National policy has to survive two different electorates, two different structures, and two different debates.

The House and the Senate Compared

The easiest way to see Congress is to compare the chambers side by side.

FeatureHouseSenate
RepresentationBy populationEqual by state
Members435 voting members100 members
ConstituencyCongressional districtEntire state
Term2 years6 years
ElectionsAll seats every 2 yearsAbout 1/3 every 2 years
Minimum age2530
Citizenship7 years9 years
Presiding leaderSpeaker of the HouseVice President
Special noteMore formal rulesMore individual influence

Representation and membership

House seats are apportioned by population after the census. California has far more House members than Wyoming. In the Senate, both get 2 senators. That is why the House reflects population differences, while the Senate does not.

Article V protects equal suffrage in the Senate. No state can lose its equal Senate representation without its consent.

Terms and elections

The House has 2-year terms, so members stay close to district opinion. Every election can reshape the whole chamber.

The Senate has 6-year terms with staggered elections, so it is a continuous body. Only about one-third is elected every two years. A wave election can flip the House fast, but the Senate usually changes more slowly.

Qualifications, size, and leadership

  • House members must be 25, citizens for 7 years, and inhabitants of their state.
  • Senators must be 30, citizens for 9 years, and inhabitants of their state.

Size shapes procedure, and AP questions love that cause-and-effect idea:

  • House is much larger, so debate is more formal and tightly limited.
  • Senate is smaller, so members have more freedom to speak, object, and influence debate.

The House is led by the Speaker. In the Senate, the constitutional presiding officer is the vice president, who only votes to break ties. In the VP’s absence, the president pro tempore presides. The Seventeenth Amendment changed senators from being chosen by state legislatures to being directly elected by voters.

Separate Powers of Each Chamber

Both chambers make laws, but some powers belong to only one chamber.

  • House only
    • Revenue bills must start here.
    • Has the sole power of impeachment.
    • Chooses the president if no candidate wins an Electoral College majority.
  • Senate only
    • Confirms presidential appointments such as judges, ambassadors, and executive officials.
    • Ratifies treaties by a two-thirds vote.
    • Tries impeachments and removes by a two-thirds vote.
    • Chooses the vice president if no candidate wins an Electoral College majority.

Lock in this distinction: the House impeaches, the Senate tries.

How Congress’s Structure Shapes Politics

Political parties are not in the Constitution, but Congress runs through the two-party system. Democrats and Republicans form caucuses, pick leaders, coordinate votes, and compete for majorities.

Because the chambers have different terms and constituencies, members behave differently:

  • House members watch short-term district opinion closely because reelection is always near.
  • Senators can take a longer view, but they must appeal to an entire state.

Party control can split. One party can control the House and the other the Senate. Add divided government, and policymaking gets harder because both chambers must still agree.

Congress’s Enumerated and Implied Powers

Article I, Section 8 lists Congress’s enumerated powers. The Necessary and Proper Clause, also called the Elastic Clause, allows implied powers needed to carry those out.

The image below is a quick reminder that Congress’s powers fit into the larger system of separated powers and checks and balances.

Study guide illustration

Branches of government and selected powers

For this section, focus on the legislative column.

Major powers include:

  • Fiscal powers
    Congress can tax, spend, borrow, coin money, pass a budget, and use appropriations. This is the power of the purse. The Omnibus Budget Reconciliation Act of 1985 is a standard example of broad fiscal legislation.
  • Military powers
    Congress can declare war and fund the armed forces, which checks the president’s role as commander in chief.
  • Naturalization
    Congress sets the national rules for becoming a citizen.
  • Interstate commerce
    Congress regulates commerce among the states. This has been a major source of national power.
  • Judiciary
    Congress creates lower federal courts and shapes much of their jurisdiction.
  • Implied powers
    In McCulloch v. Maryland, the Court said Congress could create a national bank because it was a reasonable way to carry out enumerated powers.
  • Oversight
    Congress checks the executive branch through hearings, investigations, testimony, information requests, and funding control. Oversight connects directly to lawmaking and appropriations.

Key Takeaways

The House represents people by population and the Senate represents states equally, and that split came from the Great Compromise.
Bicameralism slows lawmaking because both chambers must pass the same bill.
The size of each chamber shapes debate, with the larger House using tighter rules and the smaller Senate allowing more individual influence.
The House is more responsive to public opinion because all 435 seats are up every 2 years.
The Senate is a continuous body because only about one-third of its seats are up every two years.
Article V gives equal state representation in the Senate unusual constitutional protection.
House impeaches; Senate tries is one of the most tested chamber distinctions.
Revenue starts in the House, but appointments and treaties go through the Senate.
The Necessary and Proper Clause creates implied powers, and McCulloch v. Maryland is the classic example.
Congressional oversight is part of how Congress checks the executive branch, especially through information gathering and control of funding.

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Notes

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