A California appellate court has ruled that the First Amendment protects a journalist's publication of truthful information about a sealed arrest when the information came from a police report that the government had publicly released without restriction. The decision in Blackman v. Substack, Inc. involved journalist Jack Poulson, who wrote about Maury Blackman's 2021 arrest after an anonymous source sent him the San Francisco Police Department incident report.

The court applied the standard from The Florida Star v. B.J.F.: if a newspaper lawfully obtains truthful information about a matter of public significance, state officials may not constitutionally punish its publication absent a need to further a state interest of the highest order. The court rejected the argument that California statutes criminalizing the receipt of sealed records changed the outcome, noting Poulson did not know the report was sealed and that he was exempt under Evidence Code section 1070.

The court also found Poulson qualified as a reporter connected with an ongoing, recurring online news publication, citing O'Grady v. Superior Court. Poulson's Substack newsletter, All-Source Intelligence, published weekly with 3,000 subscribers, and his freelance work for The Guardian and The Intercept supported his status as an independent journalist. The 18-month gap between the arrest and publication did not alter the court's reasoning.