Federal appeals court upholds the Pentagon designation that bars Claude from Defense Department work

Sources: court listing, report, discussion
Summary: The D.C. Circuit opinion listing for September 2026 records the case as docket 26-1049, captioned Anthropic PBC v. United States Department of War, decided 2026-09-25. CNBC reports that the panel upheld the Pentagon designation that bars the department from using Anthropic's models and bars defence contractors from using them in department work. CNBC quotes Judge Gregory Katsas, writing for a 2-1 majority, that the department had ample support for treating continued integration of Claude into its information systems, by the department or its contractors, as a statutorily covered national-security risk, with Judge Karen LeCraft Henderson dissenting. The panel delayed the decision from taking immediate effect so Anthropic can petition for rehearing or en banc review, and a San Francisco federal judge held the parallel designation unlawful last month.
Why it matters: The designation stops the US military and its contractors from using Claude in Department of Defense work, so any programme that built on it has to move off it.
Follow-up: Track the rehearing or en banc petition, the parallel San Francisco case, and any migration guidance Anthropic or the department publishes.