Cruz v. Arizona involves John Cruz who is on death row. It’s a procedural case about whether or not an Arizona Rule of Criminal Procedure provides an “adequate and independent state law” for a judgment against Cruz. The case was heard by the Court because Arizona has refused to apply a 1994 Supreme Court precedent involving the due process right of telling the jury about a person’s ineligibility for parole if they decide against the death penalty. 

If Cruz wins, the procedural rule will be applied to his case, and according to SCOTUSBlog 30 other incarcerated people in Arizona. 

If Arizona wins, they don’t have to apply the rule in this case, or in the 30 other cases. The more liberal Justices also expressed concern about giving a roadmap to other states to avoid applying Supreme Court precedents.