"This has never happened before." US could compel Anthropic to act; simply not doing business with them is restraint, not escalation.

U.S. authorities labeled them a supply chain risk. The military went on Twitter and basically labeled Anthropic an enemy of the state. The most popular company on Earth. They did that. If USG was able to issue some kind of secret court order compelling them to act and keep it covert then they would have done it.