GEO blocking is not the same as blocking based on nationality. I'd like(?) to think someone in this decision chain realized "restricting to US nationals" meant effectively restricting it to all and chose this route knowing Antrophic would need to just pull the model (so engaging in censorship without calling it that, possibly less susceptible to court challenges).

I'm less confident in that. To me the way the announcement reads as malicious compliance -- this administration is extremely petty in its dealings, and it's not outside the realm of possibility they asked for and would have accepted an essentially symbolic ban, something that anyone with technical knowledge and a VPN could bypass.

Anthropic would have been able to talk to someone and explain how it wasn't possible to ban just "foreign nationals", and would have pointed out how nonsensical such a request was. The fact that the post does not mention any such discussion, and leaves the nonsensical request as the only stated reason, makes this feel like a power move by Dario, simply complying in the most dramatic and rage-inducing way and announcing it in a way to direct that rage at the USG. (Which is, IMO, a savvy move)