Understand Lopez
Read and annotate the case
In 1992, high school student Alfonso Lopez brought a handgun to school in San Antonio, Texas. After an initial state charge was dismissed, federal officials charged him under the Gun-Free School Zones Act of 1990. That federal law prohibited knowing gun possession in a school zone. Lopez challenged Congress’s constitutional authority to enact it.
In United States v. Lopez (1995), the Supreme Court ruled 5–4 that this law exceeded Congress’s power under the Commerce Clause. Chief Justice William Rehnquist wrote the majority opinion. The case concerned the limits of federal lawmaking power; it did not establish a Second Amendment right to bring a gun to school.
Annotate: Circle the action that federal law prohibited. Underline the constitutional issue and the Court’s answer. A holding is a legal ruling; reasoning explains why the Court reached it.
Answer questions 1 through 3
Companion case reading: https://www.oyez.org/cases/1994/93-1260
Explain the constitutional reasoning
Directions: Read the explanation. Then answer questions 4–7 using facts and reasoning from the case.
Commerce Clause, Article I, Section 8, Clause 3: Congress may regulate commerce with foreign nations, among the states, and with Indian tribes. This is a paraphrase. Interstate commerce crosses state boundaries; intrastate activity occurs within one state.
What the Court considered
The Court identified three areas Congress may regulate under its commerce power: channels of interstate commerce, such as interstate trade routes; instrumentalities, people, or things in interstate commerce, such as interstate shipments; and activities that substantially affect interstate commerce. Activity does not always have to cross a state line itself to fall within federal power.
The 1990 law regulated local gun possession, not a commercial transaction. It did not require prosecutors to establish a connection between the charged possession and interstate commerce. Nor was it an essential part of a broader regulation of economic activity.
The federal government argued that guns could cause school violence, disrupt education, reduce future productivity, and harm the national economy. The majority rejected this chain of reasoning as too indirect: if that connection were enough, almost any local activity could fall under Congress’s commerce power.
This activity concerns the 1990 provision reviewed in 1995. Do not treat its wording as a description of every later federal firearm law. Reasoning based on the majority opinion.
Compare the clauses and answer questions 8–11
Directions: Read the comparison, then answer questions 8–11. Start with the action the question asks you to explain.
| Provision or concept | Its job | What it means for Lopez |
|---|---|---|
| Commerce Clause | Authorizes regulation of interstate commerce. | The disputed source of Congress’s power; the Court found this law exceeded it. |
| Necessary and Proper Clause | Permits appropriate constitutional means of carrying out granted powers. | A useful goal alone does not establish a connection to a granted power. |
| Taxing and Spending / General Welfare | Authorizes taxation and spending for public purposes. | A federal criminal prohibition is not justified merely by calling it good for public welfare. |
| Supremacy Clause | Gives constitutional federal law priority over conflicting state law. | It cannot make a federal law constitutional when Congress lacks authority to enact it. |
Connect your cases: McCulloch allowed a national bank as a means of carrying out granted powers and blocked Maryland’s interference. Lopez enforced a limit on a claimed federal power. Like Marbury, Lopez illustrates judicial review: the Court evaluated a federal law’s constitutionality.
Several provisions may work together. The Necessary and Proper Clause is not an unlimited grant; state safety laws also remain subject to constitutional limits.
Write and score a SCOTUS comparison
Practice source: Adapted from 2024 AP U.S. Government and Politics, Set 1, Question 3. The case summary and prompts are paraphrased. Write your answers in Step 2.
Read the comparison case
Katzenbach v. McClung (1964). Ollie’s Barbecue in Birmingham, Alabama, refused to seat Black customers, offering them takeout instead. A substantial share of its food had originated outside Alabama, although the restaurant bought it through a local supplier. Its owners challenged the application of the Civil Rights Act of 1964 to their business, arguing that Congress lacked authority over its local operations.
The Supreme Court upheld application of the law. Congress had evidence that restaurant discrimination, considered across similar businesses, burdened interstate travel and trade. The restaurant’s connection to interstate food supplies supported Congress’s authority to prohibit its discriminatory practices under the commerce power.
Your three tasks
A. Name the constitutional clause at issue in both Lopez and Katzenbach. 1 point
B. Use the relevant facts of both cases to explain why the Court reached opposite conclusions about Congress’s authority. 2 points
C. Connect the Katzenbach ruling to the democratic ideal of natural rights. Explain the connection. 1 point
Build a direct answer
First: Mark the restaurant’s conduct, its interstate connection, and the Court’s ruling. All needed comparison-case information appears above.
For A: Name a clause. “Federalism” is a principle, not a clause.
For B: Identify what Congress regulated in each case. Explain why the relationship to interstate commerce justified one law but not the other. Include both rulings; avoid merely listing facts.
For C: Natural rights are inherent rights people possess, rather than privileges the government gives them. Explain how preventing racial discrimination protects rights that belong to people equally. A definition alone does not apply the idea.
Write only what each part requires. Label A, B, and C. Use complete sentences. No introduction, thesis, conclusion, quotations, or set sentence count is required.
Exam pacing: approximately 20 minutes is recommended for this question within the 100-minute FRQ section. This classroom activity has no time limit.
Exact released question on PDF page 5: https://apcentral.collegeboard.org/media/pdf/ap24-frq-us-gov-pol-set-1.pdf
Stop and write. Complete A, B, and C before opening the examples below. Use specific facts to explain the different holdings.
Put on your AP reader hat
These are original practice responses, not actual student submissions. Read each complete response, award points using this guide, and justify your scores before revealing the key.
Scoring guide
A, 1 point: Correct shared clause.
B, 0–2 points: One point for relevant Lopez facts or a holding; two total for explaining the different outcomes using both cases.
C, 1 point: Explain how the decision protects inherent rights by opposing discrimination.
Award whole points. A correct definition alone does not complete an explanation. Length, spelling, and grammar do not earn extra content points.
Practice response L1
A. Both cases used the Second Amendment.
B. Lopez was a student who brought a gun to school. Katzenbach was about a restaurant that discriminated. The Court had to decide which law it liked better, and it liked the restaurant law.
C. Natural rights means that everyone must do what the majority wants. The ruling supported what most voters wanted.
Practice response L2
A. Both cases concerned the Commerce Clause.
B. Lopez concerned a federal ban on gun possession near schools, an activity the Court found was not commercial and lacked a sufficient interstate-commerce connection under that law. The Court invalidated the ban. Katzenbach concerned discrimination by a business using interstate food supplies. Such discrimination burdened interstate trade and travel, so the Court upheld federal regulation. The different commerce connections explain the opposite holdings.
C. Natural rights belong to people inherently and equally, regardless of race. By allowing Congress to prohibit racial discrimination at the restaurant, Katzenbach protected the equal enjoyment of those rights rather than letting a business deny them because of race.
Practice response L3
A. The Commerce Clause.
B. Lopez struck down the federal school-zone gun law as exceeding Congress’s commerce power. Katzenbach was an important civil rights decision. These cases happened in different decades.
C. Natural rights are rights all people possess by being human, including life and liberty.
Score each response on your paper: A /1, B /2, C /1, total /4. Explain why each part earns or misses credit. Score only what is written. Do not imagine an explanation that the writer did not provide. A mistake in one part does not automatically erase credit earned in another.
Reveal suggested scores and explanations
Suggested practice scores
| Response | A /1 | B /2 | C /1 | Total /4 |
|---|---|---|---|---|
| L1 | 0 | 1 | 0 | 1 |
| L2 | 1 | 2 | 1 | 4 |
| L3 | 1 | 1 | 0 | 2 |
L1: A names the wrong amendment. B earns one point for the accurate fact about Lopez bringing a gun to school, but its explanation of the different rulings is incorrect. C confuses natural rights with majority rule.
L2: A names the commerce power. B links each regulated activity to its commerce connection and ruling. C explains how protection against racial discrimination reflects rights held inherently and equally.
L3: A is correct. B accurately gives the Lopez holding but never explains the restaurant’s interstate connection or the opposite outcome. C only defines natural rights; it does not connect the ruling to that ideal.
An original full credit model
A. The Commerce Clause.
B. In Lopez, Congress prohibited local school-zone gun possession without a sufficient connection to interstate commerce under the challenged law, so the Court invalidated it. In Katzenbach, the restaurant used interstate food supplies and discriminatory business practices burdened interstate trade and travel. That commercial connection supported federal regulation, so the Court upheld the law’s application.
C. Natural rights belong inherently to all people. The Katzenbach decision allowed federal protection against racial discrimination, supporting the equal enjoyment of those rights regardless of race.
What to reinforce
Facts must do explanatory work. For B, “both involved federal laws” misses why the holdings differed. For C, “it helped civil rights” needs a connection to rights that people possess inherently and equally. Do not require a particular memorized formulation when the student explains that relationship.
Part A asks about the constitutional source of power; part C asks about a democratic ideal. Commerce authority and natural-rights protection answer different questions. Natural rights is not a replacement clause for A.
The restaurant purchased food locally that had come from out of state. Do not teach that all purchases were directly from out-of-state sellers. Its local location alone did not remove it from federal commerce authority.
Revise: Improve one weak part of your own response. Label the part and explain what you changed.
Apply the concepts to a new situation
Directions: Read this original hypothetical. Write A, B, and C on your paper or in your document before reading the examples. This is a Concept Application FRQ: apply concepts to one scenario; you do not need a second court case.
Read the scenario
Congress makes ordinary disruptive talking in local school classrooms a federal crime. The law does not involve sales, interstate communication, or a broader regulation of economic activity. It requires no connection to interstate commerce in individual prosecutions. Congress argues that classroom disruption harms learning, reduces future worker productivity, and therefore damages the national economy.
A student challenges the law. A federal court applies the reasoning of Lopez and finds that Congress’s economic argument is too indirect to justify this use of the commerce power. A state legislator proposes addressing classroom conduct through state law instead.
Guidance
A: Describe the allocation of power; do not just write “federalism.” B: Connect the regulated conduct to the weakness in Congress’s commerce argument. C: Explain the state’s general authority over education or public welfare, while recognizing constitutional limits.
For this exercise, address the allocation of government power. Other possible constitutional challenges are outside the prompt. No introduction or conclusion is required; approximately 20 minutes is the AP pacing recommendation.
Judge the Concept Application examples
Response C1
A. Federalism divides authority between national and state governments. This dispute concerns Congress’s limited commerce power and the state’s authority over local schools.
B. The law must be valid because the Supremacy Clause makes every federal law stronger than anything else.
C. The state can enact any classroom law it wants because the Constitution never limits state governments.
Response C2
A. In a federal system, power is divided between the national and state governments. Congress acts under powers granted by the Constitution, while states retain general authority over areas such as education.
B. Ordinary classroom talking is noneconomic conduct, and this law has no required interstate connection. Like the argument rejected in Lopez, the claimed link from disrupted learning to future productivity would let Congress reach almost any local conduct. That supports rejecting the asserted commerce authority.
C. States have general police powers to protect health, safety, and welfare, including authority over local education. They do not need to connect every school rule to interstate commerce, but their rules must still comply with the Constitution.
Use this rubric: A describes the national/state division. B applies Lopez reasoning to these facts. C explains a state source of authority and its constitutional limits.
| Response | A /1 | B /1 | C /1 | Total /3 |
|---|---|---|---|---|
| C1 | ||||
| C2 |
Reveal suggested scores and explanations
Full credit answers and criteria
A: Federalism divides authority between national and state governments. Here, Congress claims a granted commerce power while states retain authority over local education. The response must describe a division of authority; the word “federalism” alone is insufficient.
B: The statute criminalizes noneconomic classroom behavior and requires no interstate connection. The argument from disruption to future productivity resembles the indirect chain rejected in Lopez; accepting it could erase practical limits on Congress’s commerce power. Require an accurate connection between a scenario fact and the reasoning.
C: States possess general police powers over health, safety, and welfare, including local education. A state does not need to justify every school rule through interstate commerce, though state action remains subject to constitutional limits. Require both the state source of authority and recognition of those limits, as directed by the prompt’s guidance.
Suggested practice scores
| Response | A /1 | B /1 | C /1 | Total /3 |
|---|---|---|---|---|
| C1 | 1 | 0 | 0 | 1 |
| C2 | 1 | 1 | 1 | 3 |
C1: A describes the relevant division of power. B wrongly makes supremacy a guarantee of federal validity. C incorrectly treats state authority as unlimited. Neither B nor C earns its point.
C2: A describes the allocation of power; B applies Lopez to the noncommercial conduct and indirect economic chain; C identifies state police powers and their constitutional limits. All three parts earn credit.
Possible repairs
Repair B: Supremacy cannot rescue a statute beyond Congress’s authority. This law’s connection between local classroom talking and interstate commerce is too indirect under the Lopez reasoning given in the scenario.
Repair C: A state may address school conduct through its authority over education and welfare, provided that its rule respects constitutional rights and other applicable constitutional limits.
Teaching boundary: Do not turn the classroom-talking scenario into a prediction about an actual statute or every speech restriction. The question isolates federalism and assumes the stated judicial conclusion; it does not ask students to resolve a First Amendment claim.
Read like an AP scorer
Now score actual student responses from the 2024 AP U.S. Government and Politics exam, Set 1, Question 3. They answer the Lopez–Katzenbach comparison in Step 2.
- Read samples 3A, 3B, and 3C on PDF pages 3–5. Stop before the scoring commentary on pages 6–7.
- On your paper, score each sample: A /1, B /2, C /1, total /4.
- Defend every score with evidence. Then reveal the official scores below and explain any change in your judgment.
The link opens the official PDF in a new tab. Your teacher may instead distribute only its three response pages.
Reveal the official College Board scores
Official scores
| Official sample | A /1 | B /2 | C /1 | Total /4 |
|---|---|---|---|---|
| 3A | 1 | 2 | 1 | 4 |
| 3B | 1 | 2 | 0 | 3 |
| 3C | 0 | 1 | 0 | 1 |
Reveal after students score: 3A earned every point. 3B lost C because its reference to civil rights did not explain the natural-rights connection. 3C earned only partial B credit for an accurate Lopez fact. Consult the official commentary for the complete evaluation.
The scores above were assigned by College Board. Read the full commentary on PDF pages 6–7 for its evaluation of each part.
Exit check
Teacher key and teaching notes
Have students write their own answers before opening the practice examples. Reveal the keys after students commit to scores. The activity has no time limit; divide the steps across lessons as needed.
Case analysis answers
1. Lopez brought a handgun to his high school. Federal officials prosecuted him under the Gun-Free School Zones Act of 1990.
2. Did the commerce power authorize Congress to prohibit the gun possession covered by this law? The Court held that the provision exceeded that authority.
3. The ruling evaluated the source and limits of federal authority, not the desirability of guns at school. It did not recognize a right to bring a gun to school.
4. The government connected school violence to impaired learning, reduced productivity, and adverse economic effects. Accept an accurate explanation of that chain.
5. The majority found the connection too remote. Accepting it would allow Congress to reach almost any local activity, undermining the distinction between national and state authority.
6. Federalism divides national and state authority. Limiting the asserted federal commerce power preserved space for state authority over education and public safety. This did not remove all federal involvement in those areas.
7. Congress may sometimes regulate intrastate activities with a substantial interstate-commerce connection. Lopez rejected this law’s justification, not all federal regulation of activity occurring within one state.
Teach the limit precisely
A strong answer identifies the regulated activity, the claimed power, and the missing or insufficient connection. Avoid “guns are never commerce,” “only states may regulate guns,” or “anything local is beyond federal power.” The 1990 provision also lacked a case-specific commerce requirement and was not part of a broader economic regulatory scheme.
Accept accurate reasoning in students’ own words. Do not require memorized quotations or extra doctrine beyond the prompt.
Answers to questions 8 through 11
8. Commerce Clause. The question directly involves movement of goods across state lines.
9. Taxing and Spending Clause / General Welfare language. Congress may spend for public purposes, including school safety. Appropriating money invokes spending authority; directly criminalizing local conduct requires a sufficient constitutional basis for that regulation. A worthwhile goal does not make every means constitutional.
10. The Supremacy Clause gives valid federal law priority over conflicting state law. It does not provide missing legislative authority or require courts to uphold unconstitutional statutes.
11. Federalism concerns power divided between the national and state governments. Judicial review and checks and balances concern the Court’s enforcement of constitutional limits on Congress, a relationship between branches of the national government.
Connect the three required cases
| Case | Central lesson | Precise connection |
|---|---|---|
| McCulloch | Implied powers and federal supremacy | A bank was a constitutional means of executing granted powers; Maryland could not obstruct it with the challenged tax. |
| Lopez | Limits on the commerce power | The asserted connection did not justify the school-zone possession prohibition. |
| Marbury | Judicial review | Courts can invalidate federal legislation that conflicts with the Constitution; Lopez illustrates that power. |
Explain common confusions
Second Amendment: Students see a gun and assume an individual-rights case. Ask whose power the Court was evaluating. Lopez is a federal-power decision under the Commerce Clause.
Necessary and Proper: Ask “a means of carrying out which granted power?” The clause permits appropriate constitutional means; it does not turn any beneficial policy into federal authority. Do not imply that Lopez overruled McCulloch.
General Welfare: This language supports taxation and spending, not a free-standing federal power to regulate everything that benefits society. Spending is itself an enumerated power and need not be tied to a separate enumerated regulatory power.
Supremacy and the Tenth Amendment: Supremacy presupposes constitutional federal action. The Tenth Amendment expresses reserved powers, but the disputed grant in Lopez was the Commerce Clause. “States won” alone does not explain the holding.
Official sample preparation
For a paper-based scoring exercise, print only pages 3–5 of the linked College Board PDF. Keep pages 6–7, the scoring commentary, for the reveal. The practice examples labeled L1–L3 and C1–C2 are original instructional material; only 3A–3C have official College Board scores.
Exit check model
Lopez held that the challenged school-zone possession law exceeded Congress’s commerce power because the asserted interstate connection was insufficient. The ruling neither removed all federal firearm authority nor exempted state governments from constitutional limits.