← The hardest concepts in United States law
In one breath
When a law treats groups differently, the Equal Protection Clause asks how well the government must justify the difference, and the answer depends on the classification: very strictly for race and national origin, less so for sex, and only minimally for most other lines. The higher the scrutiny, the more the government must prove about both its goal and how closely the law fits it.
The picture
The bank loan application
A bank asks for more paperwork the more it is being asked to risk. A small loan needs a pay slip. A larger one needs bank statements and a reason. A very large one needs collateral, a business plan and evidence that nothing smaller would do. Here the borrower is the government, and the loan is the power to treat people differently. The more dangerous the line it draws, the more it must show.
Two questions are asked at every size. Is the purpose good enough: a legitimate aim, an important one or a compelling one? And does the law fit the purpose: rationally related, substantially related or narrowly tailored? Race and national origin are the largest loans, sex a middle one, and age, wealth and most business regulation the smallest.
Where the picture stops working
A bank sets the size by its own view of risk, while in law the tiers are fixed by precedent and by classification. Unlike a loan officer, a court applying the top tier does not always say no: strict scrutiny is demanding, but a law can survive it. And equal protection binds the government, not private lenders.
How it really works
- 1Identify the classification the law draws, on its face or in its purpose, and confirm that the actor is a government. The Clause binds the states directly, and the federal government through the Fifth Amendment’s due process guarantee.
- 2Choose the tier. Classifications by race and national origin, and generally by alienage in state laws, draw strict scrutiny. Sex draws intermediate scrutiny. Most other classifications get rational-basis review. Laws that burden a fundamental right, such as voting, may also receive strict scrutiny.
- 3Apply the tier. Strict scrutiny requires a compelling interest and a law narrowly tailored to it. Intermediate scrutiny requires an important interest and a law substantially related to it. Rational-basis review requires a legitimate interest and a rational link.
- 4Check for purpose. A law that only has a disparate impact on a group receives heightened scrutiny if the challenger shows a discriminatory purpose, not otherwise (Washington v. Davis).
- 5Allocate the burden. Under strict and intermediate scrutiny the government must justify the law. Under rational-basis review the challenger must negate every conceivable justification.
Why people get it wrong
- Believing strict scrutiny means the law always loses. It is rarely survived, but it can be.
- Assuming unequal results alone trigger scrutiny. The classification must be drawn on a protected ground or have been adopted for a discriminatory purpose.
- Thinking the tier depends on how badly the plaintiff is hurt. It depends on the classification, or on the right burdened.
- Reading rational-basis review as a check on whether the law is wise. The court asks only whether any conceivable legitimate aim could be served rationally.
- Mixing up the tiers with First Amendment scrutiny. The words overlap, but the tests and the triggers differ.
A worked example
The facts are invented
The invented state of Fenn passes three laws. Law A says only men may hold a bartender’s license. That is a sex classification, so Fenn must show an important interest and a substantially related law. A claim that the law protects women from harm rests on a stereotype and is unlikely to be enough. Law B bars members of one racial group from state-subsidized housing. That is strict scrutiny, and Fenn would need a compelling interest and a narrowly tailored law, which is a very hard case to make.
Law C bans opticians from fitting lenses without a prescription from an optometrist. It is economic regulation that uses no suspect classification. Under rational-basis review the challenger loses if any conceivable legitimate purpose, such as protecting eye health, could rationally be served, even if the law is in practice a favor to optometrists.
Try it
A city’s entry test makes no reference to race, but nearly everyone who fails it belongs to one racial group. A challenger proves only the unequal result. What is the best reading of equal protection law?
Landmark authorities
Read the sources themselves; this list is a starting point.
- United States v. Carolene Products Co., 304 U.S. 144 (1938), footnote 4
- Williamson v. Lee Optical of Oklahoma, Inc., 348 U.S. 483 (1955)
- Craig v. Boren, 429 U.S. 190 (1976)
- Washington v. Davis, 426 U.S. 229 (1976)
Where to go next
More hard concepts in United States law
- Standing, ripeness and mootness (Constitutional law)
- The dormant Commerce Clause (Constitutional law)
- Federal preemption (Constitutional law)
- The Eleventh Amendment and state sovereign immunity (Constitutional law)
This page is an educational overview. It is not legal advice and not a substitute for the sources: the statute, the rule, the case itself. United States law is made in fifty states and in the federal system, and the rules differ between them. Each page states the usual formulation of the rule and names landmark decisions; your own state, circuit or course may use different wording. Check the primary sources before relying on any rule.