"over the past month, since Anthropic began briefing on the Mythos capability, the administration has begun taking this more seriously" [Mythos capability]
The quote directly names the specific capability demonstration (Mythos) and the specific actor (Anthropic) as the proximate cause of the administration's posture shift, supporting the claim that lab milestones now drive diplomatic agendas.
Reasoning from this article
The article shows that a single capability demonstration by a private lab reversed a government's stated policy position on AI safety diplomacy within weeks. This generalizes to a structural dynamic: as AI capabilities advance, national security establishments will increasingly be forced into reactive postures, with bilateral safety agendas shaped by lab timelines rather than diplomatic calendars. The same pattern would apply to any future capability milestone from any frontier lab in either country.