How do you resolve the security dilemma? A cursory knowledge of international relations shows why a "global pause" is basically impossible, and that's to say nothing of current international conditions. These Anthropic guys are smart, and so I can't help but think that this posture is nothing more than grandstanding to build up hype and attention ahead of the IPO.
They mention the Nuclear Forces Treaty which manages to accomplish this for a similarly difficult problem, so i believe this is technicality a solvable problem, it's just a matter of political will.