Microsoft Backs Anthropic’s Bid to Block the Pentagon’s Supply-Chain Risk Label

Microsoft warned that U.S. warfighters could be hampered if the Pentagon’s designation of Anthropic is implemented.

A man looks at his phone in front of the Microsoft logo during the 2025 Mobile World Congress in Barcelona on March 3, 2025. Albert Gea/Reuters

Microsoft on March 10 filed an amicus brief backing Anthropic’s lawsuit against the Department of War, seeking a court order to temporarily stop the Pentagon from labeling Anthropic as a supply-chain risk.

Anthropic filed the suit on March 9 after the Pentagon designated it a supply chain risk to national security, a label that would hinder the Pentagon and its contractors from using Anthropic’s artificial intelligence technology in their work for the U.S. military.