Microsoft CEO Satya Nadella attends the 56th annual World Economic Forum (WEF) meeting in Davos, Switzerland, January 20, 2026.
Microsoft threw its support behind Anthropic on Tuesday and advocated for a temporary restraining order that would block the Pentagon's supply chain risk designation "for all existing contracts."
Such a move would "enable a more orderly transition and avoid disrupting the American military's ongoing use of advanced AI," Microsoft said in a filing. "Otherwise, Microsoft and other technology companies must act immediately to alter existing product and contract configurations used by DoW. This could potentially hamper U.S. warfighters at a critical point in time."
Last week, the Department of Defense officially banned Anthropic's technology and labeled the company a supply chain risk, a label that's historically been reserved for foreign adversaries. The designation would require defense vendors and contractors to certify that they don't use Anthropic's models in their work with the Pentagon.
Anthropic sued the Trump administration on Monday, calling the government's actions "unprecedented and unlawful," and claiming that they are "harming Anthropic irreparably," putting hundreds of millions of dollars worth of contracts in jeopardy.
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