Jamal Knox is a hip-hop artist who goes by the name Mayhem Mal. Several years ago, he recorded and uploaded a music video of himself performing the song “F— the Police.”

While controversial, this is a sentiment that’s been reflected in rap music for decades. The version recorded by the 1990s rap supergroup N.W.A. helped them earn a spot in the Rock & Roll Hall of Fame. Mal’s version of the song, which named two specific police officers, landed him a two-year jail sentence in the commonwealth of Pennsylvania.

“The clear expression repeated in various ways that these officers are being selectively targeted in response to prior interactions with (Knox), stand in conflict with the contention that the song was meant to be understood as fiction,” wrote Thomas Saylor, Pennsylvania’s chief justice.

Knox, who was 19 years old at the time of his 2014 sentencing, claimed he’d been using a persona in the song. His use of a different recording name — Mayhem Mal — seems to fit with this defense. But his appeal was denied, and his lawyers are asking the U.S. Supreme Court to take up his case.

I’ve been waiting for the Defenders of Free Speech to step up and defend Knox, but they seem to be too busy suing UC Berkeley.

Still, Knox is not without powerful defenders. On Wednesday, March 6, a group of rappers — you may know them by their stage names, which include Chance the Rapper, Killer Mike, 21 Savage and Fat Joe, among others — filed a Supreme Court amicus brief, asking the justices to take up Knox’s case.

“Research tells us that listeners unfamiliar with hip-hop culture may have difficulty being reasonable when it comes to rap music because it often primes enduring stereotypes about the criminality of young black men, its primary creators,” the amici wrote in their brief.

That’s an accurate statement (social psychologist Carrie Fried discovered the same thing in her research), which also serves as a statement of interest. These performers, who are among the most successful in their field, are speaking up for Knox because they’re concerned about their own music. Sadly, they’re right to be worried.

Neither fame nor fortune nor the First Amendment has historically protected rappers from the kinds of cases that put Knox behind bars.

The list of examples is long and, frankly, embarrassing for the judicial system. From 2 Live Crew successfully defending their music against obscenity charges to Time Warner’s successful defense of Tupac Shakur’s music from liability in a Texas murder case, the fact that these cases make little sense hasn’t stopped people from trying.

Perhaps that’s why most of the rappers’ brief focuses on education. Recognizing that most of the Supreme Court justices are, ahem, let’s say unfamiliar with the process of creating rap music, they write in wonderfully academic language about the origins of their art and why they do what they do.

I highly recommend downloading the brief and handing it to the next old man you meet who’s yelling about how “the kids need to pull up their pants!” It’s all in the brief: You don’t need to offer any explanations or even say a word.

The origins of rap? In the bankrupt Bronx of the 1970s, when “(e)arly pioneers developed hip-hop, in part, to end gang violence by providing an outlet that transformed the competitiveness and territoriality of gang life into something artistic and productive.”

The roots of hip-hop’s police animus? The aggressive policing that came with the now-discredited war on drugs: “Daryl Gates, the Los Angeles Police Department chief from 1978 to 1992, openly opined in a U.S. Senate hearing that casual drug users “ought to be taken out and shot.”

An explanation of why Knox might have selected certain offensive words? “Meter and rhyme are primary, meaning that words are chosen often for their contribution to a song’s rhythm rather than its precise message.”

Reading it, I felt both pleasure and exhaustion.

Pleasure, because it’s fun to imagine a bench of old and berobed Supreme Court judges puzzling over Chance the Rapper and Killer Mike’s explanation of metaphor and poetic form. (It’s also fun to imagine them asking the Bronx-born Sonia Sotomayor for further explanations.)

Exhaustion, because it’s 2019 and rappers are still being dragged to court over a basic public misconception — the idea that they’re not artists who are capable of expressing their imaginations.

Creating a persona, crafting a melody, composing lyrics in line with a form — these are artistic endeavors. They require forethought, effort and discipline.

Yet what these court cases show, over and over again, is the expression of a belief that rappers are only capable of unthinking, personal and violent reaction. Stereotypes cost us our understanding and our common sense. Sometimes they cost people their freedom, too.