Arizona Corrections officials could soon face a First Amendment lawsuit if they refuse to overturn a ban on inmates' ability to read "Chokehold," a critically acclaimed critique of the American criminal-justice system and its treatment of black men.

The American Civil Liberties Union on Thursday challenged the book ban in a letter addressed to Corrections Director Charles Ryan, a polarizing figure already under fire for broken locks and health-care failures at Arizona prisons.

"The very people who experience extreme racial disparity in incarceration cannot be prohibited from reading a book whose purpose is to examine and educate about that disparity," ACLU attorney Emerson Sykes wrote in the letter.

Sykes called the ban "fundamentally flawed," saying "understanding of policing, incarceration, and racial bias" was particularly crucial for inmates "given Arizona’s stark racial disparities in and overall high rates of incarceration."

"To prohibit prisoners from reading a book about race and the criminal legal system is not only misguided and harmful, but also violates the right to free speech under the First Amendment of the US. Constitution and … the Arizona Constitution," he wrote.

The ACLU demanded corrections officials immediately overturn the "Chokehold" ban and review its reading-material policy "to ensure continued respect for the First Amendment rights of incarcerated persons." Lawyers said the organization will consider litigation if the department doesn't comply.

When contacted by The Republic on Thursday, corrections officials said they would comment after reviewing the letter.

Is book a true safety threat?

Sykes said the ACLU learned of the ban from "Chokehold" author Paul Butler, a former federal prosecutor from Washington, D.C.

Butler, who is African-American, wrote the book after he was arrested on false assault allegations, an event that dramatically changed his view of the justice system.

"During the trial, I experienced for myself a lot of things that defendants I’d prosecuted said were evidence of how unfair the system was: Police lied, witnesses who knew what happened didn’t come forward," Butler told The Guardian in 2017.

"The jury took less than 10 minutes to acquit me," he said, because "I could afford the best lawyer in the city, had legal skills and social standing, and because I was innocent.

"But the experience made a man out of me. It made a black man out of me."

Sykes said Corrections officials had not provided an explanation for why they banned "Chokehold." Under department policy, prohibited content can include anything that that would be “detrimental to the safe, secure, and orderly operation” of a prison.

Though "Chokehold" includes sharp and controversial criticism of police brutality and the justice system, it explicitly discourages violence of any kind.

"Under certain circumstances, it is permissible to prevent incarcerated people from reading materials of their choosing," Sykes wrote in the letter to Ryan. "However, it is unconstitutional to censor a book that educates prisoners on how legal, penal, and other institutions have shaped their own lives and poses no threat to the safety and security of the facility."

What, exactly, is 'unauthorized content'?

Corrections does not have a blanket list of prohibited magazines, newspapers, books, or music. Instead, prison clerks determine whether mail includes "unauthorized content" they should withhold from inmates.

Obvious no-nos include items that promote drug use, explain how to break locks or tie knots, or provide instructions on how to commit identity theft and other crimes.

More puzzling bans have included "The Life of Charles Dickens" and poet Maya Angelou's "I Know Why The Caged Bird Sings."

An inmate who disagrees with a ban can appeal to the department's Office of Publication Review, which sometimes will return a redacted version of the material to the inmate.

This strategy is typically used for magazines, however, not books.

Republic reporter Craig Harris contributed to this article.

Reach the reporter at maria.polletta@arizonarepublic.com or 602-653-6807. Follow her on Twitter @mpolletta.

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