10 Constitutional Law Cases Every Law Student Must Know

1. Marbury v. Madison (1803)

Judicial Review

Facts: William Marbury was appointed as a Justice of the Peace by outgoing President John Adams, but his commission was never delivered. Marbury petitioned the Supreme Court directly for a writ of mandamus compelling Secretary of State James Madison to deliver it.

Holding: Chief Justice John Marshall held that while Marbury had a right to his commission, the Supreme Court lacked original jurisdiction to issue the writ because Section 13 of the Judiciary Act of 1789 — which purported to grant that jurisdiction — was unconstitutional.

Significance: Marbury established the principle of judicial review: the power of federal courts to declare legislative and executive acts unconstitutional. It is the foundation of the entire American system of constitutional adjudication. Every subsequent case on this list exists because of the power Marshall claimed in 1803.

2. McCulloch v. Maryland (1819)

Implied Powers & Federal Supremacy

Facts: Congress chartered the Second Bank of the United States. Maryland imposed a tax on all banks not chartered by the state, targeting the federal bank. James McCulloch, a cashier at the Baltimore branch, refused to pay the tax.

Holding: Marshall held that Congress had the implied power to create a national bank under the Necessary and Proper Clause (Article I, Section 8, Clause 18), and that Maryland could not tax a federal instrumentality because the Supremacy Clause makes federal law supreme over conflicting state law.

Significance: McCulloch established a broad reading of congressional power through the Necessary and Proper Clause and reinforced the Supremacy Clause as a check on state interference with federal operations. It remains the leading case on implied powers and federal preemption.

3. Gibbons v. Ogden (1824)

Commerce Clause

Facts: New York granted a monopoly on steamboat navigation in its waters. Thomas Gibbons operated steamboats under a federal coasting license in competition with Aaron Ogden, who held the state-granted monopoly. Ogden sued to enforce the monopoly.

Holding: Marshall held that the Commerce Clause grants Congress broad power to regulate interstate commerce, including navigation. The federal coasting license preempted the New York monopoly.

Significance: Gibbons gave the Commerce Clause its expansive early interpretation, defining “commerce” to include navigation and all forms of commercial intercourse between states. This broad reading became the constitutional basis for federal regulatory power in the 20th century, from civil rights legislation to environmental law.

4. Brown v. Board of Education (1954)

Equal Protection & Desegregation

Facts: African American children were denied admission to public schools attended by white children under state laws requiring racial segregation. The cases were consolidated from Kansas, South Carolina, Virginia, and Delaware.

Holding: Chief Justice Earl Warren, writing for a unanimous Court, held that racial segregation in public schools violates the Equal Protection Clause of the Fourteenth Amendment. “Separate educational facilities are inherently unequal.”

Significance: Brown overruled Plessy v. Ferguson's “separate but equal” doctrine and launched the modern civil rights era. It established that the Equal Protection Clause prohibits state-mandated racial segregation and set the stage for strict scrutiny analysis of racial classifications. Every equal protection question on the bar exam traces its analytical framework back to Brown.

5. Miranda v. Arizona (1966)

Fifth Amendment & Custodial Interrogation

Facts: Ernesto Miranda was arrested on suspicion of kidnapping and rape. After two hours of police interrogation without being informed of his rights, Miranda signed a written confession.

Holding: The Court held that the Fifth Amendment's privilege against self-incrimination requires law enforcement to inform suspects of their rights before custodial interrogation: the right to remain silent, that anything said can be used against them, the right to an attorney, and that an attorney will be appointed if they cannot afford one.

Significance: Miranda created the now-famous Miranda warnings and established that statements obtained during custodial interrogation without these warnings are inadmissible. It is one of the most tested criminal procedure topics on both law school exams and the MBE. Practice applying Miranda doctrine with MBE criminal procedure questions.

6. Roe v. Wade (1973) & Dobbs v. Jackson (2022)

Substantive Due Process

Roe Facts: Jane Roe challenged a Texas statute criminalizing abortion except to save the mother's life. The Court applied a substantive due process analysis under the Fourteenth Amendment.

Roe Holding: The Court held that the Due Process Clause protects a right to privacy that encompasses a woman's decision to terminate a pregnancy, subject to a trimester framework balancing the state's interests.

Dobbs Holding (2022): In Dobbs v. Jackson Women's Health Organization, the Court overruled Roe, holding that the Constitution does not confer a right to abortion. The authority to regulate abortion was returned to the states.

Significance: Together, these cases illustrate the doctrine of substantive due process and the contested question of unenumerated rights. Roe was the leading case on substantive due process for nearly 50 years. Dobbs demonstrates how the Court can overrule precedent and the analytical divide between originalist and living constitutionalist approaches. Both are essential for understanding due process on the bar exam.

7. New York Times Co. v. Sullivan (1964)

First Amendment & Defamation

Facts: L.B. Sullivan, a Montgomery, Alabama city commissioner, sued the New York Times for libel over a paid advertisement that contained minor factual inaccuracies about police conduct during civil rights protests.

Holding: The Court held that the First Amendment requires a public official suing for defamation to prove actual malice: that the statement was made with knowledge of its falsity or with reckless disregard for its truth or falsity.

Significance: Sullivan created the constitutional framework for defamation law, elevating First Amendment protections for speech about public officials and public figures. The “actual malice” standard is one of the most frequently tested First Amendment doctrines on the MBE.

8. Gideon v. Wainwright (1963)

Right to Counsel

Facts: Clarence Earl Gideon was charged with felony breaking and entering in Florida. Too poor to afford a lawyer, he requested that the court appoint one. The trial judge denied the request because Florida law only provided appointed counsel in capital cases. Gideon represented himself, was convicted, and petitioned the Supreme Court from prison.

Holding: The Court unanimously held that the Sixth Amendment's right to counsel is a fundamental right incorporated against the states through the Fourteenth Amendment's Due Process Clause. States must provide counsel to indigent defendants in all felony cases.

Significance: Gideon established that the right to counsel is essential to a fair trial and must be provided at state expense when a defendant cannot afford an attorney. It later extended to misdemeanor cases involving imprisonment (Argersinger v. Hamlin). This case is foundational for both criminal procedure and the incorporation doctrine.

9. Mapp v. Ohio (1961)

Exclusionary Rule

Facts: Cleveland police forcibly entered Dollree Mapp's home without a valid search warrant, claiming to search for a bombing suspect. During the search, they discovered obscene materials and arrested Mapp for possession.

Holding: The Court held that the exclusionary rule — which prohibits the use of evidence obtained through unconstitutional searches and seizures — applies to state courts through the Fourteenth Amendment's Due Process Clause.

Significance: Mapp incorporated the Fourth Amendment's exclusionary rule against the states, making illegally obtained evidence inadmissible in all American courts. It is the reason defense attorneys file motions to suppress evidence and one of the most tested Fourth Amendment principles on the bar exam. For MBE practice on search and seizure, use Lorea's free practice questions.

10. Citizens United v. FEC (2010)

Corporate Speech & Campaign Finance

Facts: Citizens United, a nonprofit corporation, wanted to air a film critical of a presidential candidate within 30 days of a primary election. The Bipartisan Campaign Reform Act (McCain-Feingold) prohibited corporations and unions from funding “electioneering communications” near elections.

Holding: The Court held that the First Amendment prohibits the government from restricting independent political expenditures by corporations, associations, and labor unions. The spending restrictions in McCain-Feingold were struck down as unconstitutional.

Significance: Citizens United extended First Amendment protection to corporate political speech, holding that the identity of the speaker does not diminish the protection afforded to political expression. The decision transformed campaign finance law and remains one of the most debated First Amendment cases. It tests students' understanding of the scope of free speech protections and the level of scrutiny applied to content-based restrictions.

How to Study These Cases Effectively

Reading case summaries is a start, but it won't prepare you for exams or the bar. To truly internalize these holdings, use active study methods:

• Brief each case using IRAC. For every case, write out the Issue, Rule, Application, and Conclusion in your own words. Our complete IRAC guide shows you exactly how.
• Test yourself with practice questions. Upload your con law casebook or outline to Lorea's PDF-to-questions tool and generate MBE-style questions on each case.
• Create condensed summaries. Use AI-generated summaries to distill lengthy opinions into the key facts, holdings, and reasoning.
• Practice under MBE conditions. Constitutional law questions on the MBE require you to apply these doctrines to novel fact patterns under time pressure. Read our MBE preparation guide for the complete strategy.

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