Microsoft has called out the Pentagon for misusing its national security authority in a landmark court filing in a San Francisco federal court in support of Anthropic’s challenge to the Defense Department’s supply-chain risk designation. The filing argued that the designation, never before applied to a US company, was an abuse of government power that threatened critical technology supply chains. Amazon, Google, Apple, and OpenAI have also backed Anthropic through a separate joint filing.
The Pentagon’s alleged misuse of authority began when it labeled Anthropic a supply-chain risk following the breakdown of a $200 million contract in which the company refused to allow its Claude AI to be used for mass surveillance or autonomous lethal weapons. Defense Secretary Pete Hegseth formalized the designation, and the Pentagon’s technology chief publicly ruled out any renegotiation. Anthropic filed two simultaneous lawsuits in California and Washington DC challenging the designation.
Microsoft’s public calling out of the Pentagon is grounded in its own direct integration of Anthropic’s technology into federal military systems and its participation in the $9 billion Joint Warfighting Cloud Capability contract. The company also holds additional federal agreements spanning defense, intelligence, and civilian agencies. Microsoft publicly argued that the government and technology sector must cooperate to ensure advanced AI serves national security responsibly.
Anthropic’s court filings argued that the supply-chain risk designation was an unconstitutional act of ideological retaliation for its publicly stated AI safety positions. The company disclosed that it does not currently believe Claude is safe or reliable enough for lethal autonomous operations, which it said was the genuine basis for its contract demands. Anthropic emphasized that this designation had never before been applied to a domestic American company.
Congressional Democrats have separately demanded answers from the Pentagon about whether AI was used in a strike in Iran that reportedly killed over 175 civilians at a school. Their formal inquiries ask specifically about AI targeting tools and human oversight. Together, Microsoft’s public calling out, the industry coalition, and congressional scrutiny are creating an extraordinary accountability moment for the Pentagon’s use of national security authority in the context of AI governance.