The Rational Basis Test: A Story

Adam Shelton · February 10, 2021

Before the Rational Basis Test

Constitutional litigation is more complicated than many might think. One could not be faulted for thinking that if a right is protected by the Bill of Rights, including the Ninth Amendment, then the government cannot violate that right. But not all rights are equal—at least not in the eyes of the federal judiciary.

Some rights, like free speech, will receive meaningful protection from the judiciary. When evaluating laws challenged as a violation of free speech, the courts will generally apply something known as “strict scrutiny.” This means that the court will only uphold the law if the government can prove that it is narrowly tailored to achieve a compelling government interest. Courts will also require such a showing if the law discriminates against discrete and insular minorities.

But other rights are not so lucky. Private property rights and the right to earn an honest living are generally only protected by the rational basis test. When a person challenges a licensing law for violating his right to earn an honest living the court will require her to prove that the law is not rationally related to any legitimate government purpose. That is, for most rights, the burden is on individuals to prove that the government is violating their rights, rather than requiring the government to prove what it is doing is constitutional.

What is more, the courts are very lax in determining whether something is “rationally related.” What makes a law rationally related to a legitimate government purpose can be totally hypothetical. Further, the “legitimate government purpose” does not even have to be the real purpose. In practice, this means that the government can enact otherwise unconstitutional laws so long as they can think up some hypothetical constitutional purpose served by the law.

But where did this test come from? It certainly is not required by the Constitution! And it did not even appear regularly until the late 1930s. This series will address just that question. It will trace the development of the rational basis test before it was even a “test” but just a philosophical idea about laws and the legislature.

The Precursors to the RBT: Harlan & Holmes

The rational basis test developed slowly over time. Many pinpoint its creation with the Supreme Court’s 1938 decision in Carolene Products. But that case just set the stage for it to be used more frequently. Its roots run deeper and its development can be seen in the opinions of the first Justice Harlan, who sat on the Supreme Court from 1877-1911 (not to be confused with his grandson with the same name, who served from 1955-1971). Take, for example, his majority opinion in Mugler v. Kansas, a case challenging Kansas’ prohibition on the sale and manufacture of any “intoxicating liquor.” Justice Harlan, writing for the majority upholding the law explained that overturning this prohibition would amount to judges usurping the “legislative functions” and overturning the “will of the people” enacted through their legislators.

Nearly a decade later, Justice Harlan, this time in dissent, expounded on this idea in Plessy v. Ferguson, the infamous “separate but equal” decision. While Justice Harlan was correct in the merits of his dissent, he rejected arguments from Louisiana by using the principle that underlies the rational basis test. Louisiana, responding to the suggestion that the law requiring separate rail cars based on race was no different than requiring different cars for Catholics and Protestants, different cars for naturalized citizens and native citizens, a sheriff segregating a court room based on color, or segregating legislative halls or political rallies based on color, argued that the difference was that those would be unreasonable, while rail car segregation was not.

Justice Harlan rejected this argument, but not for the correct reason. He did not reject it because Louisiana was just wrong arguing that segregation was reasonable. Rather, he rejected it because he did not believe that it was the role of the courts to determine whether something was reasonable, to look behind any laws to see if there were any nefarious, or unconstitutional, motives in enacting a given law. In other words, for Justice Harlan, whether a law is reasonable is not a question for the judiciary.

This theme continued in Justice Harlan’s dissent in Lochner v. New York. This now controversial case dealt with New York’s maximum hour law for bakers. Bakers could not work in the bakery for more than 60 hours in a week. The case started when Joseph Lochner was charged and convicted of allowing a baker to work more than 60 hours in a week. His main defense was that this statute was an unconstitutional impairment on his right to contract. Both the Appellate Division of the Supreme Court and the N.Y. Court of Appeals upheld the law over dissents. But the tide turned at the Supreme Court.

The Supreme Court struck down the maximum hour limitation because it violated the 14th Amendment’s protection of the liberty to contract. The majority then underwent a serious analysis of the law explaining that “whether it is or is not repugnant to the Constitution of the United States must be determined from the natural effect of such statutes when put into operation, and not from their proclaimed purpose.” That is, the court is to look “beyond the mere letter of the law” when the proclaimed purpose is protecting public health, but its real-life operation does no such thing. This is method of looking to see how the law actually operates is “real judging.” It requires the government to present real evidence for its decision to impair the constitutional liberties of individuals.

Compare this to the dissenting opinion of Justice Harlan. Harlan explained that it was “plain that this statute was enacted in order to protect the physical well-being of those who work in” bakeries. He determined that there was certainly some connection between health and hours worked, and that was enough to satisfy the Constitution. Justice Harlan explained “that legislative enactments should be recognized and enforced by the courts as embodying the will of the people, unless they are plainly and palpably, beyond all question, in violation of the fundamental law of the Constitution.” This language is quite similar to the ideas that animate the rational basis test—that only the unquestionably unconstitutional will be struck down, but the probably unconstitutional will be upheld.

This idea that the legislative enactments should be upheld unless undoubtably unconstitutional in the era before the rational basis test reached a high-water mark in Buck v. Bell. This is where Justice Holmes makes his return in a three-page 8-1 decision allowing the government to forcibly sterilize certain women, including Carrie Buck. As Justice Holmes explained, the state calls on the best people to lay down their lives in war so “[i]t would be strange if it could not call upon those who already sap the strength of the State for these lesser sacrifices, often not felt to be such by those concerned, in order to prevent our being swamped with incompetence.”

But what makes this case truly a precursor of the rational basis test is how very little the justices were concerned with the facts. They took for granted that Carrie Buck was a promiscuous and mentally challenged woman. Yet she always maintained that she was raped, which is what led to her having a child out of wedlock. Further, the Supreme Court accepted that she had mental difficulties, ignoring the fact that her school records showed otherwise. That is, the Supreme Court took the government at its word that it had a good reason for sterilizing Carrie Buck. It did not make the government present evidence to that effect and it did not weigh the competing evidence. It took the government at its word that she was promiscuous and an “imbecile.” Accepting the government’s assertions as true is the hallmark of the rational basis test.

Footnote 4 Ushers in the RBT

Each of these cases, and the constitutional theories presented, were precursors to, and are the underlying theory of, the rational basis test. The formulation of the rational basis test as we know it can be seen as far back as 1877 in Munn v. Illinois. There, the Supreme Court held that Illinois did not violate the Constitution by establishing maximum rates for grain storage. The court explained that “[i]f no state of circumstances could exist to justify such a statute, then we may declare this one void, because [it exceeded] the legislative power of the State. But if it could, we must presume it did.” That is, if there was any circumstance to justify the challenged statute, courts will assume that it does justify it and meets constitutional muster.

This formulation came up again through the years including in Nebbia v. New York and West Coast Hotel v. Parrish. But its use was disjointed until 1938 when the Supreme Court decided United States v. Carolene Products. There the Supreme Court determined that the federal government did not violate the constitution by prohibiting a type of milk from being shipped in interstate commerce. But Carolene Products is remembered much more for a footnote than its actual holding.

Footnote 4 of Carolene Products officially split constitutional rights into two categories. One category consisted of rights that the court deemed “important.” These rights would receive real protection from the judiciary. The other category consisted of rights not seen as important and thus would not receive meaningful judicial protection from government overreach. This footnote did not create the rational basis test. But it gave it utility. It created circumstances in which courts could employ this test on a consistent basis.

Looking Forward

The rational basis test allows the government to restrict individuals’ rights so long as there is any conceivable legitimate basis for doing so. The real reason the government is doing so is immaterial to the courts. This means that so long as there is a conceivable justification for the law, a court will uphold it, even if the government’s true purpose is unconstitutional.

My next few posts will track the evolution of this test. They will review the higher profile cases and present the stories behind the court cases. Finally, they will offer some hope that the most deferential form of the rational basis test is on its way out.


Adam Shelton is a fellow with IJ’s Center for Judicial Engagement