Key Clauses of the Constitution

The Supremacy Clause (Article VI)

The Constitution, federal laws made "in Pursuance thereof," and treaties are "the supreme Law of the Land," and state judges are bound by them. When a valid federal law conflicts with a state law, the federal law prevails. This is called preemption. Federal law can preempt state law expressly, or by occupying an entire field such as immigration.

Interpretation: In McCulloch v. Maryland (1819), Maryland could not tax the national bank because "the power to tax involves the power to destroy." A state cannot obstruct valid federal action. In Cooper v. Aaron (1958), the Court held that Arkansas officials were bound by Brown v. Board of Education. Note that the Supremacy Clause covers only valid federal law. A federal law that exceeds Congress's powers is not supreme.

The Full Faith and Credit Clause (Article IV)

"Full Faith and Credit shall be given in each State to the public Acts, Records, and judicial Proceedings of every other State." Congress may prescribe how such records are proved and what effect they have.

In practice: a court judgment won in Florida can be enforced in Georgia. Birth certificates, deeds, and adoption decrees from one state are honored in others. A marriage performed in one state is generally recognized elsewhere. After Obergefell v. Hodges (2015), all states must license and recognize same-sex marriages. That ruling rested on the Fourteenth Amendment, not on Full Faith and Credit. Driver's licenses are honored among states mainly by interstate agreement and state law.

The clause turns thirteen, now fifty, separate legal systems into a working union. The Articles of Confederation had a similar provision.

The Commerce Clause (Article I, Section 8)

Congress has power "To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes." Under the Articles of Confederation, states had taxed each other's goods and Congress could do nothing. The clause was meant to create a national market.

How its reading has changed

• Gibbons v. Ogden (1824): Chief Justice Marshall read "commerce" broadly to include navigation. A federal license beat a New York steamboat monopoly.
• Late 1800s–1937: The Court often read the clause narrowly and distinguished manufacturing from commerce. It struck down some early New Deal and child-labor laws.
• 1937–1995: The Court upheld nearly any regulation of activity that, in the aggregate, substantially affects interstate commerce. Examples include Wickard v. Filburn (1942), on home-grown wheat, and Heart of Atlanta Motel v. United States (1964), which upheld the Civil Rights Act of 1964's ban on discrimination in public accommodations serving interstate travelers.
• United States v. Lopez (1995): Carrying a gun near a school is not economic activity, and the Court struck down the Gun-Free School Zones Act. This was the first major limit on the clause in nearly 60 years.
• NFIB v. Sebelius (2012): The Commerce Clause did not allow Congress to require people to buy health insurance. The Court nevertheless upheld the Affordable Care Act's mandate as a tax.

The Emoluments Clauses

An emolument is a payment, salary, profit, or benefit from an office or service. The Constitution has two emoluments clauses:

• Foreign Emoluments Clause (Article I, Section 9): "no Person holding any Office of Profit or Trust under them, shall, without the Consent of the Congress, accept of any present, Emolument, Office, or Title, of any kind whatever, from any King, Prince, or foreign State." Its purpose is to prevent foreign influence and corruption of federal officials. Officials who receive foreign gifts must generally turn them over or get Congress's consent. Congress has set rules by statute.
• Domestic Emoluments Clause (Article II, Section 1): the president's compensation cannot be increased or decreased during the term, and the president may not receive "any other Emolument from the United States, or any of them." This keeps Congress and the states from bribing or punishing a president through pay.

The same section of Article I also bans the United States from granting titles of nobility. The emoluments clauses have rarely been tested in court. Lawsuits about them in the late 2010s ended without a Supreme Court ruling on their merits.

The Due Process Clauses (5th and 14th Amendments)

"Nor shall any person … be deprived of life, liberty, or property, without due process of law" (5th, federal). "Nor shall any State deprive any person of life, liberty, or property, without due process of law" (14th, states).

Interpretation:

• Procedural due process: fair procedures, as in Gideon (counsel) and Miranda (warnings).
• Incorporation: the 14th Amendment clause applies most of the Bill of Rights to the states (selective incorporation).
• Substantive due process: protection for certain unlisted fundamental rights. Roe v. Wade (1973) found a right to privacy covering abortion. Dobbs v. Jackson Women's Health Organization (2022) overruled Roe, holding that the Constitution does not confer a right to abortion and returning the issue to the people and their elected representatives. Obergefell rested on both due process and equal protection.

See also Due Process (Chapter 3).

The Equal Protection Clause (14th Amendment)

"Nor [shall any State] deny to any person within its jurisdiction the equal protection of the laws."

Interpretation over time:

• Plessy v. Ferguson (1896) upheld "separate but equal."
• Brown v. Board (1954): "Separate educational facilities are inherently unequal."
• Baker v. Carr (1962) made apportionment challenges reviewable, leading to "one person, one vote."
• Bakke (1978) struck down racial quotas in admissions while allowing race as one factor. In Students for Fair Admissions v. Harvard (2023), the Court held that race-conscious admissions programs at Harvard and the University of North Carolina violated the Equal Protection Clause and Title VI.
• Shaw v. Reno (1993) subjected race-based district lines to strict scrutiny.
• Bush v. Gore (2000) held that varying recount standards violated equal protection.

The Necessary and Proper (Elastic) Clause (Article I, Section 8)

Congress may "make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States." It is called the Elastic Clause because it "stretches" Congress's powers to cover means not listed. It is the source of implied powers.

The great debate: In 1791, Treasury Secretary Alexander Hamilton argued that "necessary" meant useful or conducive, so Congress could charter a national bank. Secretary of State Jefferson argued for a strict reading, "necessary" meaning indispensable. In McCulloch v. Maryland (1819), Chief Justice Marshall sided with Hamilton's broad construction: "Let the end be legitimate, let it be within the scope of the constitution, and all means which are appropriate, which are plainly adapted to that end, which are not prohibited, but consist with the letter and spirit of the constitution, are constitutional."

Anti-Federalists such as Brutus feared exactly this clause. They warned it would let Congress do almost anything. See Brutus No. 1.

The First Amendment Clauses

The two religion clauses can pull in different directions. Accommodating religion too much may look like establishment, and enforcing separation too strictly may burden free exercise. Courts try to keep government neutral, neither promoting nor hindering religion.

Other Clauses Worth Knowing

• General Welfare / Taxing and Spending Clause (Art. I, Sec. 8): Congress may tax and spend to "provide for the common Defence and general Welfare." It supports federal grants with conditions.
• War Powers: Congress declares war (Art. I); the president is commander in chief (Art. II). See the War Powers Resolution.
• Privileges and Immunities (Art. IV) and the Privileges or Immunities Clause (14th Amendment).
• Habeas Corpus Clause (Art. I, Sec. 9).
• Elections Clause (Art. I, Sec. 4).
• Guarantee Clause (Art. IV, Sec. 4): a republican form of government.
• Takings Clause (5th Amendment): just compensation for property taken for public use.