  Security risks from AI have motivated calls for international agreements that
guardrail the technology. However, even if states could agree on what rules to
set on AI, the problem of verifying compliance might make these agreements
infeasible. To help clarify the difficulty of verifying agreements on
AI$\unicode{x2013}$and identify actions that might reduce this
difficulty$\unicode{x2013}$this report examines the case study of verification
in nuclear arms control. We review the implementation, track records, and
politics of verification across three types of nuclear arms control agreements.
Then, we consider implications for the case of AI, especially AI development
that relies on thousands of highly specialized chips. In this context, the case
study suggests that, with certain preparations, the foreseeable challenges of
verification would be reduced to levels that were successfully managed in
nuclear arms control. To avoid even worse challenges, substantial preparations
are needed: (1) developing privacy-preserving, secure, and acceptably priced
methods for verifying the compliance of hardware, given inspection access; and
(2) building an initial, incomplete verification system, with authorities and
precedents that allow its gaps to be quickly closed if and when the political
will arises.
