Slave patrols prevented slave revolts, captured runaway slaves and kept watch on “free” Blacks. They policed the South. In many jurisdictions, notably Charleston, South Carolina, slave patrols morphed into the official police force.

Slave patrols went obsolete after the Civil War. So why does American apartheid persist despite the Thirteenth, Fourteenth, and Fifteenth Amendments?

The antebellum mainstream had stereotyped African-Americans as “natural slaves.” For the last 150 years, the mainstream has stereotyped them as natural-born criminals to rationalize the totalitarian police state into which they have mass-incarcerated African-Americans. In the aftermath of failed Reconstruction, the Ku Klux Klan (on the one hand) and modern police (on the other hand) replaced the slave patrols.

Consider that J. Edgar Hoover, the twentieth century’s greatest American police officer, persecuted Black human rights advocates from Marcus Garvey to Martin Luther King, Jr. as if they were criminals. The founder and director of the FBI once called the Black Panther Party, a human rights organization, “the greatest threat to the internal security of the country.” His FBI used COINTELPRO (an acronym standing for “COunterINTELligence PROgram”) to frame civil rights organizations such as the National Association for the Advancement of Colored People as “communist” in order to justify the FBI’s intent to “expose, disrupt, misdirect, or otherwise neutralize” groups it considered “subversive.”

President Richard Nixon mandated “law and order.” He appointed “strict constructionist” Supreme Court justices to expand police power. Yet the unkindest cut came from the Warren Court’s 1968 Terry v. Ohio decision, which redacted the constitutional “probable cause” limitation of police power.

The Fourth Amendment’s “probable cause” is the standard by which police have reason to obtain a warrant to arrest a suspected criminal, or to search or seize a person or his property. But ever since Terry v. Ohio, police officers have had the despotic discretion to search or seize, or arrest, any American citizen based on a “reasonable suspicion” that they are a criminal or are about to commit a crime.

Despite William Douglas’ great dissent, Terry v. Ohio effectively sanctioned police stereotyping. It enabled “stop and frisk”, allowing police officers to detain, question and search civilians. It criminalized walking while Black and driving while Black.

According to social critic Walter Lippmann’s classic “Public Opinion” (1922), stereotypes frame our perceptions because they tell us about the world before we see it. Stereotypes lead us to imagine things before we experience them.

Lippmann explains: “And those preconceptions, unless education has made us acutely aware, govern deeply the whole process of perception. They mark out certain objects as familiar or strange, emphasizing the difference, so that the slightly familiar is seen as very familiar, and the somewhat strange as sharply alien.”

Whites tend to be “very familiar” to, and African-Americans “sharply alien” to, mainstream cops. Presidential politics reinforce these negative Black stereotypes. When President Woodrow Wilson screened D.W. Griffith’s “The Birth of a Nation” at the White House in 1915, he legitimized the Ku Klux Klan. When President George H.W. Bush televised the Willie Horton ad while running for president in 1988, he won the white paranoid vote through the dangerous Black male stereotype. And in 1996 Hillary Clinton, as First Lady, stereotyped Black youths as “superpredators.”

President Donald Trump is now the “law and order” president. He wants to double down on “stop and frisk.” But the presumption of innocence, the idea that every American is innocent until proven guilty, is fundamental to due process.

The Trump presidency should take seriously Coffin v. U.S. (1895): “The principle that there is a presumption of innocence in favor of the accused is the undoubted law, axiomatic and elementary, and its enforcement lies at the foundation of the administration of our criminal law.” The alternative is Dred Scott v. Sandford (1857): “The Negro has no rights which white men are bound to respect.”

The Fourteenth Amendment mandates that no “state deprive any person of life, liberty, or property, without due process of law.” It would overturn Dred Scott if only cops would obey its implicit command that they be street-level constitutional experts. Here’s Lippmann on “expertise”: “Expertness in any subject is, in fact, a multiplication of the number of aspects we are prepared to discover, plus the habit of discounting our expectations. Where to the ignoramus all things look alike, and life is just one thing after another, to the specialist things are highly individual.”

The street-level constitutional expert respects the dignity of every American. They ensure that people within their purview get due process of law. Due process is no mere technicality. It is their moral imperative. What the prime directive is to the space explorers of “Star Trek”—a check and balance on their power toward the peoples they encounter throughout the galaxy—due process is to the well-trained police officer.

Checks and balances set the pattern of our constitution. Police officers are of the executive branch; the judicial branch passes judgment on alleged criminals. But the police officer dreaming of “Dirty Harry” plays judge, jury and executioner. He deranges our system of checks and balances. He lacks the police officer’s professional character, which recognizes that every person on American soil is innocent until proven guilty in a court of law.

All American citizens command respect from their public servants. Yet cops routinely kill or harass African-Americans as criminal stereotypes who “all look alike” and thus “fit the description.” The street-level constitutional expert individualizes all Americans, citizens and noncitizens alike. He presumes them innocent. He protects their life, liberty, and property. He understands that racial profiling is un-American. To him Black lives matter, for he sees African-Americans as citizens, not stereotypes.