Microsoft backs Anthropic’s lawsuit against Pentagon’s AI supply-chain risk label.

Microsoft has filed a legal brief supporting Anthropic’s lawsuit against the Pentagon, urging a judge to block the Defense Department’s designation of the AI company as a supply-chain risk. The tech giant argues the designation threatens its own operations, as it relies on Anthropic’s Claude AI models, and could force costly system changes across the industry. The move highlights growing concerns over how national security designations impact AI innovation and commercial partnerships.