WASHINGTON — Five years ago, Chief Justice John G. Roberts Jr. enlivened a Supreme Court argument by reciting raw and violent lyrics from the rapper Eminem. The chief justice said he was worried that ignoring the song’s musical and cultural context could “subject to prosecution the lyrics that a lot of rap artists use.”

That case, about online threats in a domestic dispute, ended in a cryptic muddle. But now the issue Chief Justice Roberts raised in passing is squarely at the court’s doorstep, in an appeal from a Pittsburgh rapper sent to prison for two years for threatening police officers — in a song.

This time, the justices will have expert assistance from a group of hip-hop stars, including Chance the Rapper, Meek Mill, Killer Mike, Yo Gotti, Fat Joe and 21 Savage. In a brief filed Wednesday, they urged the Supreme Court to hear their fellow rapper’s First Amendment challenge to his conviction.

[Read the brief here.]

They also offered the justices, whose average age is about 66, what they called “a primer on rap music and hip-hop.”