A federal appeals court heard arguments Tuesday regarding a lawsuit by AI startup Anthropic to block the Pentagon from blacklisting the company [1, 2].

The case centers on whether the U.S. government can label a private technology provider a national security risk based on the company's internal policies or public stances. If the court rules in favor of Anthropic, it could limit the government's ability to exclude vendors from military contracts based on supply-chain risk designations.

The U.S. Court of Appeals for the District of Columbia Circuit in Washington, D.C., held the oral arguments on May 19, 2026 [1, 2]. Anthropic is suing Defense Secretary Pete Hegseth and the Department of Defense [1].

The dispute began after the Pentagon labeled Anthropic’s AI system a national-security supply-chain risk, which barred the military from using the technology [3, 4]. Anthropic said this label is an unlawful act of retaliation that violates the company's First Amendment rights [3, 4].

Anthropic filed its lawsuit against the Defense Department in March 2026 [1]. The legal challenge follows a previous ruling on March 26, 2026, in which U.S. District Judge Rita Lin described the Pentagon’s blacklisting as "classic illegal First Amendment retaliation" [2].

The Pentagon said the designation is necessary for national security. However, the appeals court judges appeared divided during the hearing over the legal merits of the dispute [2]. The court must now determine if the government's supply-chain risk assessment was a legitimate security measure or a pretext for punishing the company's speech.

“Anthropic argues that this label is an unlawful act of retaliation that violates the company's First Amendment rights.”

This ruling will establish a critical precedent for the intersection of national security and corporate free speech. If the court upholds the 'supply-chain risk' label, the Pentagon gains broad authority to exclude AI firms from government work based on security concerns. Conversely, a victory for Anthropic would force the Department of Defense to provide more transparent, evidence-based justifications for blacklisting vendors to avoid accusations of political retaliation.