Anthropic’s Pentagon showdown is drawing Silicon Valley into a larger fight

The dispute between Anthropic and the Department of Defense is quickly becoming a broader test of how far the government can go in policing AI companies’ policies—and how much support those companies can rally from the wider research community.

A fair showing of top AI researchers had already signed a public letter backing Anthropic. Now 37 of them have taken a more formal step, signing an amicus brief filed with the court Monday.

The filing underscores how the clash is evolving...