The more AI is seen as an existential or strategic threat, the more likely a sudden breakthrough could spark a crisis akin to the Cuban missile crisis. For example, imagine a Chinese lab reaching recursive self-improvement with progress accelerating to possibly strategically decisive levels in the span of hours or days. Posing a threat of irreversible strategic loss for other stakeholders, such a crisis could escalate to military and even nuclear conflict, and would likely be more difficult to de-escalate than previous crises have been; it's much harder to verifiably stop such AI development than it is to remove some missiles from Cuba.
Based on public information, preparedness for this kind of crisis appears minimal and poorly coordinated, and if classified plans exist, they are not serving an external signaling or deterrence function:
In practice, a sudden breakthrough would result in a massive scramble to negotiate internally and externally on how to react. Without pre-negotiated protocols for pausing frontier development, the only credible responses available to other actors may be coercive ones.