The legal challenge that the Arizona Supreme Court is considering was brought by the anti-abortion advocacy group Center for Arizona Policy and the Arizona Free Enterprise Club, a dark money nonprofit. They were joined by two anonymous donors who alleged they feared harassment and violence if their political spending was disclosed. They argued that mandating disclosure of the source of political spending violates the Arizona Constitution’s protections of free speech, association, privacy and separation of powers. Under federal tax law, neither the Arizona Free Enterprise Club or the Center for Arizona Policy’s political arm have to disclose donors. Alexander Samuels, an attorney representing the Arizona Attorney General’s Office, made similar arguments, adding that the disclosures are focused on large money donors.