The Defense Department has moved roughly ninety percent of its classified artificial intelligence workloads off Anthropic models and expects to finish the transition by the end of September, a timeline pulled forward from the previously reported October target. All Maven Smart System and Palantir work migrated months ago. The replacement set is deliberately plural: OpenAI's ChatGPT, xAI's Grok, and Google's Gemini are named explicitly, with eight further vendors unnamed.
Under Secretary of Defense for Research and Engineering Emil Michael framed the move as a hedge against single-vendor concentration rather than a judgment on any one model, asking what the department would do if its sole supplier failed to keep pace: "What if that model were Gemini or some other model that hadn't kept up with the frontier?" The operational feedback reported alongside the policy rationale is blunter — warfighters are said to prefer recent ChatGPT releases to Anthropic's models, and to find Grok "way faster than both."
The substantive dispute underneath the migration is about usage restrictions. Anthropic sought contractual limits on mass surveillance applications and on fully autonomous weapons employment. The department declined those terms, holding that models procured for national security work must be available for all lawful purposes without vendor-imposed carve-outs, and subsequently designated the company a national security supply chain risk. That designation is the part with the longest reach: it converts a commercial disagreement over acceptable-use policy into a procurement status that follows the vendor across programs.
For the wider field this is the clearest test yet of whether a frontier lab can hold a usage-policy line against its largest sovereign customer and keep the account. The answer here is no. The structural consequence is that a lab's safety commitments now carry a measurable procurement cost, and that defense AI capacity is being deliberately spread across a larger vendor pool so that no single supplier's policy choices can constrain the department again.