Not all anniversaries are good ones. Thursday marked a troubled one in American history . On this date in 1896, the Supreme Court handed down its decision in Plessy v. Ferguson. 

The case concerned a Louisiana law mandating segregated railway cars according to race. The 7-1 outcome declared that legally prescribed segregation did not necessarily violate the 14th Amendment. So long as the state segregated on basically equal terms for all races and did so for a reasonable purpose, then such laws would be upheld, the court decided. Hence, we get from this case the phrase “separate but equal,” which was used to justify the Jim Crow era, especially in the South.

We can find much to criticize in the decision. In that criticism, we see lessons many still have not fully learned today. The obvious one regards race. The majority denied that legal distinctions based on skin color necessarily declared one race superior or inferior to another.

Justice John Marshall Harlan, the case’s lone dissenter, skewered this view. He pointed out that the supposed neutrality regarding race in the law really ignored its true foundation. The law purported to protect the safety of all persons against possible disorder and violence that might occur in integrated railway cars. But why did the risk of such disorder and violence exist? It existed predominately because white people would not want to be in cars with African Americans due to a feeling of racial superiority. The Louisiana law took this private prejudice and turned it into a public statute.

Though legal segregation has long been illegal now, we could still learn much from Harlan and his vision of true equality. Race-based programs still exist, and though they claim no animus toward any person based on their skin color, the effects are much the same. If one digs to the bottom of affirmative action, as well as diversity, equity, and inclusion requirements, for example, one usually finds racial assumptions, implicit or explicit. These assumptions often involve moral condemnation of persons of one race and disrespectfully low views of the prospects of those in others.

This point leads to Harlan’s broader one. He famously declared that the Constitution is “colorblind and neither knows nor tolerates classes among citizens.” For Harlan, this didn’t mean that persons could not have a cultural heritage they privately acknowledged, even celebrated for good or ill. But it did mean the Constitution enacted America’s commitment to human equality before the law in the protection of their fundamental, natural rights. However persons might privately think and act, the government established and regulated by the Constitution must only see equal human beings when it acts.

The Supreme Court must remember this principle as it considers a case that could end affirmative action programs in all state-run or state-funded institutions. Doing so would be a vindication of our founding principles and move the government away from the treacherous waters of legalized racial distinctions. As Justice Clarence Thomas wrote in the last major affirmative action case in 2003, “Every time the government places citizens on racial registers and makes race relevant to the provision of burdens or benefits, it demeans us all.”

There is another lesson Plessy can teach us. The majority argued that law could play no helpful part in mitigating, much less eliminating, racial prejudice among citizens. All the law could do was regulate against actions of fraud or violence. In so saying, the court made a broader claim: that the law could not aid in shaping the moral character of the people.

On this point, too, we should reject the majority. Laws do not merely restrain; they teach. They bestow the moral authority of the law in approving some actions and prohibiting others. A logical and moral people will take seriously such authority and often can be habituated by following it toward a better understanding of justice. There are limits to the law’s capacity here, both in that laws can be unjust and that humans are fallible. But laws can and must be part of forming citizens’ character, lest we legally treat each other as little better than beasts.

So let us mark the anniversary of Plessy. But let our condemnations neither be arrogant nor mindless. Let us see in it our flaws. And let us learn from them how to do better here and now.

Adam Carrington is an associate professor of politics at Hillsdale College.