The ACLU has challenged the Arizona Department of Corrections' decision to ban prisoners from accessing a book that explores how racial disparities plague the U.S. criminal justice system.

In a letter released on their website, ACLU lawyer Emerson Sykes questioned the decision to ban the book. Sykes wrote, "The ADC cannot show that banning Chokehold is reasonably related to legitimate penological interests and should immediately correct its decision and restore access to Paul Butler's important book."

"Chokehold explores how racial disparities plague the U.S. criminal justice system and how to address those deep inequalities and injustices. Paul Butler, a former federal prosecutor, draws on the chokehold as a metaphor to dissect how various structures exert power over Black men in particular," the ACLU wrote.

In March, the Arizona Department of Corrections deemed the book “unauthorized content” and banned inmates from reading it. Prison departments in states across the country routinely ban books they decide are controversial, prompting ACLU threats or lawsuits.

The ACLU recently threatened both North Carolina and New Jersey for banning prisoners from access to The New Jim Crow by Michelle Alexander. The ACLU was successful, forcing both states to rescind those bans. 

"Nothing in the book threatens to disrupt the facility's ability to maintain security and order," the ACLU added.

"ADC's position regarding Chokehold unsoundly asserts that educating incarcerated individuals on the penal system and their legal rights threatens the security of the prison operations."

Butler is now a criminal law professor at Georgetown University but decided to write the book after his own experience fighting unfair charges in the justice system.

In interviews with The New York Times and The Associated Press, Butler said the decision to ban his book was indicative of the very ideas the book discusses. 

“I found the ban somewhat ironic because it’s kind of supporting the thesis,” he said. 

“The thesis in ‘Chokehold,’ that black men are targeted by police and prosecutors, that’s not going to be breaking news to any inmate who’s in prison in Arizona.”

Like most states, Black people in Arizona make up a higher percentage of the prison population than they do of the state population. About 5 percent of Arizona residents are Black, while 14.5 percent of the prison population is Black.

“In order for them to ban a book, they have to show the restriction is related to a legitimate prison interest. There’s no interest to keep inmates from learning about the criminal justice system and policing,” Sykes told Newsweek.

Spokesman for the Arizona Department of Corrections Andrew Wilder told The New York Times they were reviewing the letter and would respond but declined to make any further statements. 

“One in 19 black men are in prison in Arizona right now. Rather than acknowledge it’s a good thing that inmates want to read about and debate important public policy, Arizona pushes back against rehabilitation, against literacy, against the Constitution,” Butler told Newsweek.

The Arizona Department of Corrections has already been under fire for banning four issues of a magazine that covered sexual assault committed by prison guards.