>I really don't see how anybody could think a private defense contractor should be entitled to countermand the military by leveraging the control it has over products it has already sold. Maybe the terms of their contract entitled them to some discretion over what orders the product will carry out, but there's no such claim in the OP.

I don't think that is what is happening. What most likely is happening is that they want Anthropic to produce new systems due to the success of the previous ones, but they are refusing to do so because the new systems are against their mission. What seems like the DoD is attempting to do, on one hand, is call them a supply chain risk to limit Anthropic's business opportunities with other companies, and then, on the other hand, simultaneously invoke DPA so that they can compel them to make the new system. But why would the government want to compel a company to make a system for them due to a need for national prepareness that they designated as such a supply chain risk that they forbid other companies that provide government services from doing business with due to the national security risk of having a sabotaged supply chain? It doesn't really make sense, other than from a pure coercion perspective.