Some famous Supreme Court cases are worth knowing because they still govern how American law works today: who can be prosecuted, who can marry, what police must say before questioning you, when a federal agency’s rules bind the public, and what the Constitution actually protects. The decisions below are grouped by the question each one answered, from the earliest ruling that gave the Court power to strike down laws to a 2024 decision that reshaped federal regulation.
Cases That Built Federal Power
Marbury v. Madison, decided in 1803, established judicial review. Chief Justice John Marshall held that when a federal law conflicts with the Constitution, courts have the authority to strike it down. The dispute itself was about a judicial appointment, but the lasting result was the Court’s conclusion that part of the Judiciary Act of 1789 was unconstitutional, which made the Supreme Court the final interpreter of what the Constitution means.1Justia. Marbury v. Madison
McCulloch v. Maryland answered whether Congress has powers beyond those listed in the Constitution. When Maryland tried to tax a branch of the Second Bank of the United States, the Court ruled that Congress could create the bank under the Necessary and Proper Clause even though banking is never mentioned in the Constitution, and that states cannot tax or interfere with federal operations.2Justia. McCulloch v. Maryland The decision opened the door to a broad reading of federal authority.
Gibbons v. Ogden extended that authority into commerce. New York had granted a monopoly over steamboat traffic in its waters, and the Court struck it down, holding that Congress’s power to regulate interstate commerce includes navigation and reaches across state lines. When federal and state commercial regulations conflict, federal law controls.3Justia. Gibbons v. Ogden
Limits on Presidential Power
United States v. Nixon came out of the Watergate scandal. President Nixon refused to produce White House tape recordings, claiming executive privilege. The Court recognized a qualified privilege for presidential communications but held it is not absolute: when the evidence is needed for a criminal trial, that need outweighs the president’s interest in confidentiality.4Justia. United States v. Nixon Nixon resigned within weeks.
Trump v. United States, decided in 2024, took up a question no earlier case had squarely answered: whether a former president can be prosecuted for things done while in office. The Court set out a three-tier framework. A former president has absolute immunity for acts within the core constitutional powers of the presidency, presumptive immunity for other official acts, and no immunity at all for unofficial conduct.5Justia. Trump v. United States The Court acknowledged that distinguishing official from unofficial acts will not always be easy, leaving lower courts to work out the line.
Racial Equality
Plessy v. Ferguson, decided in 1896, upheld a Louisiana law requiring separate railroad cars for Black and white passengers, reasoning that separate facilities did not violate the Constitution as long as they were roughly equal.6National Archives. Plessy v. Ferguson “Separate but equal” then supplied the legal cover for decades of state-enforced segregation.
Brown v. Board of Education dismantled that doctrine in 1954. A unanimous Court held that racially segregated public schools are inherently unequal, even when the buildings and materials are comparable, because separating children by race generates a sense of inferiority that affects their education in ways that cannot be made up for.7Justia. Brown v. Board of Education of Topeka
Loving v. Virginia carried equal protection into marriage. In 1967, the Court unanimously struck down state laws banning interracial marriage, finding that such statutes served no purpose other than racial discrimination and violated both the Due Process and Equal Protection Clauses.8Justia. Loving v. Virginia
Students for Fair Admissions v. Harvard, decided in 2023, ruled that the race-conscious admissions programs at Harvard and the University of North Carolina violated the Equal Protection Clause. The majority found the programs lacked measurable objectives and used racial categories that were overbroad, effectively overruling earlier decisions that had permitted limited consideration of race in college admissions.9Justia. Students for Fair Admissions, Inc. v. President and Fellows of Harvard College
Rights of the Accused
Mapp v. Ohio applied the exclusionary rule to state courts in 1961. Evidence that police obtain through unconstitutional searches cannot be used in a state criminal trial, because the Fourth Amendment reaches the states through the Fourteenth.10Justia. Mapp v. Ohio The rule gave the Fourth Amendment a direct consequence inside the courtroom.
Gideon v. Wainwright came two years later. Clarence Gideon, charged with a felony in Florida, could not afford a lawyer, was forced to represent himself, and lost. He petitioned the Supreme Court from prison. In 1963, a unanimous Court held that the Sixth Amendment right to counsel is fundamental and that states must provide an attorney for any criminal defendant who cannot afford one.11Justia. Gideon v. Wainwright Retried with a public defender, Gideon was acquitted. The decision built the modern public defender system.
Miranda v. Arizona, decided in 1966, addressed custodial interrogation. Before questioning a suspect in custody, police must inform the person of the right to remain silent, that anything said can be used in court, the right to an attorney, and the right to an appointed attorney if the suspect cannot afford one. Statements obtained without those warnings are generally inadmissible.12Justia. Tinker v. Des Moines Independent Community School District The familiar warning police recite during arrests comes from this ruling.
Terry v. Ohio governs the far more common street stop. In 1968, the Court held that an officer with a reasonable suspicion that someone is involved in criminal activity may briefly detain the person, and if the officer also reasonably believes the person may be armed, may conduct a limited pat-down of outer clothing for weapons. That is a lower standard than the probable cause needed for a full arrest or search.13Justia. Terry v. Ohio Whether an officer’s suspicion was truly reasonable remains one of the most litigated questions in criminal procedure.
Speech and Religion
Tinker v. Des Moines settled whether students keep First Amendment rights at school. In 1969, after students were suspended for wearing black armbands to protest the Vietnam War, the Court declared that students do not “shed their constitutional rights to freedom of speech or expression at the schoolhouse gate.” Protected expression can be restricted only when it materially and substantially disrupts the school’s operations.12Justia. Tinker v. Des Moines Independent Community School District
New York Times Co. v. Sullivan rebuilt libel law to protect the press. An Alabama jury had awarded $500,000 to a city commissioner over factual errors in an advertisement about civil rights. The Court reversed, holding that a public official suing for defamation must prove “actual malice,” meaning the publisher knew the statement was false or acted with reckless disregard for the truth.14Library of Congress. New York Times Co. v. Sullivan The actual malice standard still governs defamation claims brought by public figures.
Citizens United v. FEC, decided in 2010, struck down federal restrictions that barred corporations and unions from spending their own money on political communications near an election. The majority held that the government cannot suppress political speech based on the speaker’s corporate identity and that the First Amendment protects independent political expenditures regardless of whether the speaker is a person or an organization.15Justia. Citizens United v. Federal Election Commission
Kennedy v. Bremerton School District, decided in 2022, redrew the Establishment Clause line. A public high school football coach was fired for kneeling in personal prayer on the field after games. The Court ruled his prayers were protected private speech rather than government-endorsed religion, because he prayed during a period when school employees were free to engage in personal activities. The decision also formally abandoned the Lemon v. Kurtzman test courts had used for decades, replacing it with an approach grounded in historical practices and understandings.16Justia. Kennedy v. Bremerton School District
Privacy, Abortion, and Marriage
Roe v. Wade, decided in 1973, held that a woman’s decision to end a pregnancy fell within a constitutional right to privacy drawn from the Fourteenth Amendment. The Court set out a trimester framework: in the first trimester, the decision belonged to the woman and her doctor; in the second, states could regulate the procedure to protect maternal health; and after viability, states could restrict or ban abortion except when the mother’s life or health was at risk.17Justia. Roe v. Wade
Dobbs v. Jackson Women’s Health Organization overruled Roe in 2022. The Court held that the Constitution does not confer a right to abortion, concluding that such a right is not “deeply rooted in this Nation’s history and tradition.” The majority found Roe’s historical analysis flawed and said Casey v. Planned Parenthood, which replaced the trimester framework with an “undue burden” standard in 1992, had papered over the same problems. Authority over abortion regulation returned to the states.18Justia. Dobbs v. Jackson Women’s Health Organization The result is a patchwork of state laws, with some states banning abortion almost entirely and others affirmatively protecting access.
Obergefell v. Hodges, decided in 2015, applied liberty and equal protection principles to same-sex marriage. The Court held that the Fourteenth Amendment requires every state to license marriages between two people of the same sex and to recognize such marriages performed in other states.19Justia. Obergefell v. Hodges Same-sex couples gained the same legal benefits and responsibilities as opposite-sex couples, from tax filing to hospital visitation to inheritance.
The Second Amendment
For most of American history, the Supreme Court said almost nothing about the Second Amendment. District of Columbia v. Heller changed that in 2008. The Court held for the first time that the Second Amendment protects an individual right to possess a firearm unconnected with militia service, including for self-defense in the home, and struck down Washington, D.C.’s handgun ban. The Court also emphasized the right is not unlimited: prohibitions on possession by felons, bans on carrying firearms in sensitive places like schools and government buildings, and regulations on commercial gun sales remain permissible.20Justia. District of Columbia v. Heller
New York State Rifle & Pistol Association v. Bruen went further in 2022. New York required concealed-carry permit applicants to show “proper cause,” which gave licensing officials discretion to deny permits to ordinary citizens. The Court struck down the requirement and set a new test: when the Second Amendment’s text covers an individual’s conduct, that conduct is presumptively protected, and the government must show its regulation is consistent with the nation’s historical tradition of firearms regulation.21Justia. New York State Rifle and Pistol Association, Inc. v. Bruen The history-and-tradition approach replaced the means-end scrutiny lower courts had been applying and has produced a flood of litigation over which modern gun laws have sufficient historical parallels.
Federal Agency Power
For forty years, a doctrine called Chevron deference shaped federal regulation. Under the 1984 decision in Chevron v. Natural Resources Defense Council, courts deferred to a federal agency’s reasonable interpretation of an ambiguous statute the agency administered. When Congress wrote a vague law and an agency filled in the details through regulation, courts largely accepted the agency’s reading.
Loper Bright Enterprises v. Raimondo ended that era in 2024. The Court overruled Chevron, holding that the Administrative Procedure Act requires courts to exercise their own independent judgment when deciding whether an agency has acted within its statutory authority. Courts no longer defer to an agency’s interpretation just because a statute is ambiguous.22Justia. Loper Bright Enterprises v. Raimondo Agency interpretations still carry persuasive weight, but they no longer get automatic deference. The ruling affects nearly every area of federal regulation, from environmental rules to financial oversight to workplace safety, because agencies can no longer count on courts accepting their reading of an unclear statute.