Rational basis review
Based on Wikipedia: Rational basis review
Imagine a legal test so deferential to the government that, as Justice Thurgood Marshall once quipped, it essentially means "the Constitution does not prohibit legislatures from enacting stupid laws." That test exists. It's called rational basis review, and it's the default setting for how American courts evaluate most challenges to government action.
When someone argues that a law violates their constitutional rights—whether under the Due Process Clause or the Equal Protection Clause—the court must decide how closely to scrutinize that law. Should judges put the law under a microscope, demanding compelling justifications from the government? Or should they defer to legislators, presuming the law is constitutional unless something is obviously wrong?
Rational basis review is the latter approach, taken to its logical extreme.
The Lowest Bar in Constitutional Law
Under rational basis review, a law survives constitutional challenge if it is "rationally related" to a "legitimate" government interest. That might sound reasonable enough. But the way courts actually apply this test makes it nearly impossible for challengers to win.
Here's the catch: the government doesn't even have to explain its actual reasons for passing the law. Courts will hypothesize justifications on the government's behalf. If judges can imagine any conceivable legitimate purpose the law might serve—even one the legislature never considered—the law stands.
The Supreme Court has stated explicitly that under this standard, it is "entirely irrelevant" what end the government is actually seeking. Statutes can be based on "rational speculation unsupported by evidence or empirical data." Judges understand themselves to be "obligated to seek out other conceivable reasons for validating" challenged laws, even if the government cannot justify its own policies.
This creates an almost absurd situation. The government brings a law to court. The court asks why this law exists. The government shrugs. And the court says, "Well, we can think of a reason, so it's constitutional."
A Hierarchy of Scrutiny
To understand why rational basis review matters, you need to understand where it sits in the hierarchy of constitutional review. American courts use three main levels of scrutiny, each reflecting a different degree of judicial suspicion toward government action.
Strict scrutiny sits at the top. When a law burdens a "fundamental right"—like free speech, religious exercise, or the right to vote—or when it draws distinctions based on a "suspect classification" like race, courts demand that the government prove the law is "narrowly tailored" to achieve a "compelling" interest. Most laws fail this test. It's sometimes called "strict in theory, fatal in fact."
Intermediate scrutiny occupies the middle ground. Courts apply this to laws involving "quasi-suspect classifications" like gender or legitimacy of birth. Here, the government must show the law is "substantially related" to an "important" government interest. Not as demanding as strict scrutiny, but still meaningful.
Rational basis review sits at the bottom. It applies to everything else—which means most laws. Economic regulations. Zoning ordinances. Professional licensing requirements. Unless a law touches a fundamental right or targets a protected class, it gets rational basis review.
The practical consequence? Laws reviewed under strict scrutiny usually fall. Laws reviewed under intermediate scrutiny have a fighting chance. Laws reviewed under rational basis almost always survive.
Where This Idea Came From
The intellectual foundation for rational basis review traces back to 1893, when Harvard law professor James Bradley Thayer published an influential article arguing that courts should invalidate statutes only when their unconstitutionality is "so clear that it is not open to rational question." Thayer believed in judicial restraint—the idea that unelected judges should defer to the democratic choices of elected legislators.
One of Thayer's students was Oliver Wendell Holmes Jr., who would become one of the most influential justices in Supreme Court history. Holmes articulated an early version of rational basis thinking in his famous dissent in the 1905 case Lochner v. New York.
Lochner is one of those cases that law students study as a cautionary tale. The Supreme Court struck down a New York law limiting bakery workers to sixty hours per week, reasoning that it violated the "liberty of contract" protected by the Fourteenth Amendment. Holmes thought this was nonsense—judges imposing their economic preferences under the guise of constitutional interpretation.
The word 'liberty', in the 14th Amendment, is perverted when it is held to prevent the natural outcome of a dominant opinion, unless it can be said that a rational and fair man necessarily would admit that the statute proposed would infringe fundamental principles as they have been understood by the traditions of our people and our law.
Holmes was arguing for deference. Let the people, through their legislatures, make economic policy. Courts should intervene only when no rational person could think the law constitutional.
The Lochner Era and Its End
Holmes lost that battle, at least initially. For the next three decades—a period historians call the "Lochner era"—the Supreme Court regularly struck down economic regulations as violations of substantive due process. Minimum wage laws, worker protection statutes, regulations of business practices: the Court treated "liberty of contract" as a fundamental right deserving aggressive judicial protection.
The Lochner era ended in the 1930s, partly due to political pressure during the Great Depression and President Franklin Roosevelt's threat to "pack" the Court with additional justices. In 1934, the Court decided Nebbia v. New York, upholding a New York law setting minimum prices for milk. The opinion announced a new principle: "a State is free to adopt whatever economic policy may reasonably be deemed to promote public welfare, and to enforce that policy by legislation adapted to its purpose."
This was rational basis review taking shape. The Court was stepping back from economic regulation, leaving those decisions to legislatures.
Footnote Four and the Two-Track System
Four years after Nebbia, the Supreme Court decided United States v. Carolene Products Co., a case about filled milk that would have been forgotten entirely if not for a single footnote.
Footnote Four, perhaps the most famous footnote in constitutional law, suggested that while most legislation deserves deferential review, some laws might warrant "more exacting judicial scrutiny." Which laws? Those that appear to violate a "specific prohibition of the Constitution." Those that "restrict the political process" by which majorities can be changed. And those that burden "discrete and insular minorities" who cannot protect themselves through normal democratic channels.
This footnote became the blueprint for modern constitutional law. It created a two-track system. Economic regulations and ordinary legislation get rational basis review—near-automatic approval. But laws touching fundamental rights or burdening minority groups get heightened scrutiny—genuine judicial examination.
The logic was about institutional competence. Legislatures are generally better at making policy decisions than courts. But when the political process itself is broken—when majorities use their power to entrench themselves or to harm groups that can't fight back politically—courts have a special role to play.
How Deferential Is Too Deferential?
Rational basis review is sometimes criticized as being no review at all. If courts will hypothesize justifications the government never offered, if evidence is irrelevant, if any conceivable basis suffices, then what exactly are courts doing?
The honest answer is: not much. In 2008, Justice John Paul Stevens acknowledged this frankly, recalling Justice Marshall's observation that the Constitution does not prohibit stupid laws. Rational basis review means courts will uphold laws that are foolish, counterproductive, or based on outdated assumptions—as long as they're not entirely irrational.
But "entirely irrational" is a high bar. A law fails rational basis review only when every conceivable justification for it is, in the Court's words, "a grossly illogical non sequitur." Almost nothing qualifies.
Consider what this means in practice. A state could require florists to have professional licenses, ostensibly for consumer protection, even if there's no evidence unlicensed florists harm anyone. A city could zone adult bookstores out of residential areas based on assumptions about crime that might not hold up empirically. An economic regulation could favor one industry over another for reasons that amount to political favoritism. All of this passes rational basis review.
The Occasional Exception
Occasionally—very occasionally—a law fails rational basis review. These cases often involve what some scholars call "rational basis with bite," where courts seem to apply more skeptical analysis while nominally using the deferential standard.
Romer v. Evans, decided in 1996, is a notable example. Colorado voters had passed an amendment to their state constitution prohibiting any locality from enacting anti-discrimination protections for gay and lesbian residents. The Supreme Court struck it down, finding that the amendment was so broadly drawn and served no legitimate purpose other than expressing "animus" toward a particular group.
But Romer was unusual. Most rational basis cases follow the predictable pattern: challenger loses, government wins, law stands.
The Democratic Tradeoff
There's a deeper principle at work here, one that goes to the heart of debates about judicial power in a democracy. Who should make policy decisions—elected legislators or unelected judges?
Proponents of rational basis review argue it reflects appropriate judicial humility. Judges aren't economists or social scientists. They can't know whether a minimum wage helps or hurts workers, whether licensing requirements protect consumers or entrench incumbents, whether this zoning rule serves the public good. These are empirical questions on which reasonable people disagree. Better to let the democratic process work, even if it produces imperfect results.
Critics counter that this deference can become abdication. If courts won't examine whether laws actually serve their stated purposes, they provide no check against legislative overreach, special-interest capture, or simple irrationality. The Constitution protects liberty and equality. That protection is hollow if any law passes muster simply because a judge can imagine some hypothetical justification.
Where Rational Basis Applies Today
In modern constitutional law, rational basis review applies to challenges against both federal and state laws. It governs both legislative and executive action. It covers both substantive questions (does this law violate a constitutional right?) and procedural ones (did the government follow fair procedures?).
The basic requirement is this: government cannot impose restrictions on liberty that are genuinely irrational or arbitrary. It cannot draw distinctions between people that serve no constitutionally legitimate end. But as long as a law bears "a rational relationship to a legitimate governmental purpose"—and nearly any plausible purpose will do—it survives.
This means most constitutional challenges to economic regulations fail. Most challenges to professional licensing schemes fail. Most challenges to ordinary legislation that doesn't touch fundamental rights or protected classes fail.
The Constitution, it turns out, does not prohibit legislatures from enacting stupid laws. It prohibits only the ones that are completely, utterly, demonstrably irrational—and even those just barely.
A Standard That Shapes Strategy
Understanding rational basis review matters for anyone trying to challenge government action. It shapes legal strategy from the outset.
If your case will receive rational basis review, you probably shouldn't bring it at all. The odds are overwhelming that you'll lose. Your resources would be better spent lobbying the legislature to change the law, or supporting candidates who share your views, or engaging in public advocacy. The political process, not the courts, is where you'll find relief.
If you want judicial protection, you need to convince the court that heightened scrutiny applies. Frame your claim as touching a fundamental right. Argue that the law burdens a suspect or quasi-suspect class. Find a way into the upper tiers of the scrutiny framework, where courts actually examine the government's justifications.
The level of scrutiny often determines the outcome. That's why so much constitutional litigation is really about which test applies, not about applying the test itself. Win on the standard of review, and you've usually won the case.
The Quiet Background Rule
Rational basis review rarely makes headlines. The cases that reach the Supreme Court—the ones about abortion, affirmative action, free speech, religious liberty—almost always involve heightened scrutiny. Those are the battles where outcomes are uncertain and stakes are high.
But rational basis review governs the vast majority of government action. It's the quiet background rule that makes ordinary legislation possible. Without extreme judicial deference to legislative choices, every economic regulation, every licensing requirement, every zoning ordinance would be vulnerable to constitutional challenge.
Whether that deference has gone too far—whether courts should more aggressively police even ordinary legislation—remains contested. Some legal scholars argue for reviving more robust review of economic regulations, echoing the Lochner era's skepticism of government intervention in markets. Others defend the current approach, warning that aggressive judicial review would substitute judges' policy preferences for democratic choices.
For now, rational basis review remains the default. Most laws pass. Most challenges fail. And the Constitution, for better or worse, does not prohibit stupid laws.