I'd encourage you to look up the Defense Production Act. Its powers are probably broad enough that the President could unilaterally force Anthropic to do this whether or not it wants to. It's the same logic that would allow him to force an auto manufacturer to produce tanks. And the law doesn't care whether we are in a crisis or not. It's enough that he determine (on his own) that this action is "necessary or appropriate to promote the national defense."

However, it looks like Trump isn't going to go that route-- they're just going to add Anthropic to a no-buy list, and use a different AI provider.