US judge rules Pentagon’s blacklist of Anthropic unlawful, calls it First Amendment retaliation

A federal judge has blocked the Pentagon from treating Anthropic as a supply chain risk, ruling that the designation was likely an act of illegal retaliation against the AI company for speaking publicly about safety and refusing to strip restrictions from its models.

US District Judge Rita F. Lin issued a preliminary injunction on March 26, finding that the Department of Defense’s blacklisting of Anthropic appears to violate the First Amendment. In a 43-page opinion, she described the government’s actions as “classic illegal First Amendment retaliation,” drawing a sharp line between legitimate national security concerns and what she characterized as punitive overreach.

How the standoff started

The conflict traces back to Anthropic’s refusal to comply with Pentagon requests to remove safety guardrails from its AI models. Specifically, the company declined to allow its technology to be deployed for surveillance or autonomous lethal weaponry, positions consistent with its longstanding public commitments on AI safety.

Defense Secretary Pete Hegseth escalated the situation on February 27, issuing directives that formally designated Anthropic as a supply chain risk. The label, which had never previously been applied to a US company, effectively locked Anthropic out of defense contracting.

The designation landed in the middle of negotiations over a $200 million Department of Defense agreement, where the Pentagon maintained it had the authority to dictate how contractors’ technology could be used.

On March 9, Anthropic filed lawsuits in both the Northern District of California and the D.C. Circuit, arguing the designation constituted unlawful retaliation and suffered from procedural defects.

Two courts, two outcomes

Judge Lin in Northern California sided firmly with Anthropic, granting the preliminary injunction and finding the company was likely to succeed on the merits of its First Amendment claim. Her opinion highlighted a glaring mismatch between the government’s stated national security rationale and the timeline of events, which pointed more toward retaliation than genuine risk assessment.

Over in the D.C. Circuit, a three-judge panel denied Anthropic’s emergency stay request on April 8, weighing in favor of governmental equities and citing active military operations. That ruling didn’t reach the merits of Anthropic’s claims but reflected a more deferential posture toward executive branch authority in defense matters.

What the ruling means for AI and defense

The case is without direct precedent. No US company had previously been hit with a supply chain risk designation of this kind, a tool typically reserved for foreign adversaries or entities with documented security vulnerabilities.

At its core, the dispute forces a confrontation between two competing visions of how AI should be governed. The Pentagon’s position implies that companies seeking defense contracts must accept military specifications without conditions, including the removal of safety-oriented usage restrictions. Anthropic’s position, now backed by at least one federal court, is that the government cannot weaponize procurement decisions to punish companies for their public advocacy on how AI should and shouldn’t be used.

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