After the clerk at the convenience store confirmed that nothing unusual had happened, the officers drove Graham home. He was left with a broken foot, several lacerations, and what he would later describe as a persistent ringing in his right ear. Little did Graham know as he writhed in pain that this episode would lead, five years later, to one of the most important U.S. Supreme Court decisions in modern history, Graham v. Connor. While the decision stemming from this incident is not well known, its influence has been far-reaching.

Since the beginning of the Black Lives Matter movement, in 2013, stories concerning police use of force have been prominent in the news and on social media. Much of the public conversation has focused on a collective exasperation: How is it that police can beat and kill men and women, many of them unarmed, yet rarely be held accountable?

The answer lies in large part in the 1989 Graham decision. Graham brought a federal claim against the Charlotte police officers, under a civil-rights statute called 42 U.S.C. §1983, in the U.S. District Court for the Western District of North Carolina. He argued that the excessive use of force against him violated substantive due process, or his right to be free from such abuse under the Fourteenth Amendment—one of the Reconstruction amendments ratified after the Civil War to give African Americans full legal equality with whites.

The trial court, as well as the Fourth Circuit Court of Appeals, sided with the officers. But, in deciding to review the case, the Supreme Court made a surprising move. Until that point, the legal standards through which federal courts reviewed claims of excessive force by state and local police were diverse. Many cases used substantive due process under the Fourteenth Amendment, following an earlier Second Circuit Court of Appeals decision in Johnson v. Glick, in which a detained man alleged that a correctional officer had assaulted him. This standard had been criticized, however, for emphasizing officers’ subjective mental state—that is, whether the force was applied in “good faith” or “maliciously and sadistically for the very purpose of causing harm.”

In the Graham decision, the Supreme Court held that substantive due process was not the applicable constitutional standard. Rather, the Court said the proper constitutional test was whether the action was “reasonable” under the Fourth Amendment, which prohibits unreasonable searches and seizures. (Use of force by the police during an arrest or investigative stop is understood to be a type of “seizure.”)

The choice was significant. Turning away from the Fourteenth Amendment as a constitutional standard would come to represent a missed opportunity to situate excessive force in minority communities as a long-standing structural problem. The Fourth Amendment was developed at a time when slavery was condoned by the Constitution, and it is largely preoccupied with the relationship between individuals and the government. The Fourteenth Amendment, on the other hand, has its roots in the post–Civil War effort to extend legal equality to former slaves. Particularly through its clause guaranteeing equal protection of the law, it reflects an awareness of how racial groups, not just individuals, can face state persecution. (Although the Fourteenth Amendment’s due-process clause is what allows the Fourth Amendment to apply to state and local police, as opposed to only the federal government, the Graham decision nonetheless represents a significant retreat from the Fourteenth Amendment’s original purpose of protecting racial minorities from state violence and other inequities.)