Anthropic petitioned the U.S. Court of Appeals for the D.C. Circuit on October 13 for a rehearing of its challenge to the Pentagon's designation of the company as a national security supply-chain risk. A divided panel upheld that designation in September in a 2-1 decision.

Anthropic argues the panel read a law aimed at hostile foreign actors far too broadly, and that the designation was imposed without a pre-designation process despite evidence it was retaliation for the company's public AI safety positions. The underlying dispute began after Anthropic refused to allow its models to be used for autonomous weapons or mass surveillance.

The designation bars defense contractors from using Claude on Pentagon work, which Anthropic says has cost it billions in lost business. A separate California case struck down a parallel designation in August on First Amendment grounds, so the two tracks now point in opposite directions.