Anthropic urges court in Washington, D.C. to rehear appeal of Pentagon blacklisting

Key points

• Anthropic asks a Washington, D.C. federal court to rehear its appeal over the Pentagon's blacklisting.
• The Pentagon applied the supply chain risk label in March, blocking contractors from using Claude.
• A 2-1 D.C. Circuit ruling in September upheld the blacklisting; a San Francisco judge ruled against it in August.

Anthropic has asked a federal court in Washington, D.C. to rehear its appeal in a case about the Pentagon's blacklisting of the company's AI models. The petition was filed on Tuesday.

The Defense Department, led by Pete Hegseth, applied a supply chain risk label in March. That move blocked defense contractors from using Anthropic's technology in their work with the agency, after negotiations over how the military could use Anthropic's Claude AI models broke down.

What the filing says

Anthropic's attorneys wrote that the Secretary of War branded the company a national-security supply chain risk because it declined to allow its models to be used for mass surveillance of Americans or lethal autonomous warfare, and publicly explained those AI-safety commitments. They said a divided panel upheld that designation.

The attorneys also wrote that the court ignored what they called straightforward evidence that the designation was retaliation for Anthropic's speech about AI safety.

The Secretary of War branded Anthropic — an American AI company whose models help defend the nation— a national-security 'supply chain risk'

— Anthropic attorneys

Earlier rulings in the case

Anthropic sued the Trump administration to undo the action. In September, the D.C. Circuit upheld the Pentagon's blacklisting in a 2-1 decision that rejected Anthropic's argument that the ban on its Claude models was arbitrary, unauthorized and unconstitutional.

In a parallel case, a San Francisco federal judge ruled in August that the DOD had violated Anthropic's First Amendment rights and that the supply chain risk designation amounted to illegal retaliation.

Company and Pentagon responses

Before the dispute became public earlier this year, Anthropic was an early partner across many U.S. agencies, including the DOD. It signed a $200 million contract with the Pentagon in July of 2025, but talks collapsed that September as the company negotiated Claude's deployment on the DOD's GenAI.mil AI platform.

An Anthropic representative declined to comment beyond the filing. A Pentagon spokesperson told CNBC by email that the agency does not comment on pending or ongoing litigation.