Political Exit as an Ex Ante Choice Set: Measuring Actor-Initiable Alternatives in Premodern China

Existing work links political fragmentation to greater elite exit ability, including movement from one polity to another. The historical measurement problem is narrower and prior to any substantive fragmentation claim: at the moment a political center turns against a particular actor, how can we know whether an apex-independent alternative actually belonged to that actor’s ex ante choice set? This paper develops a conservative actor × decision-time × political-node measure. A positive option requires three separately coded conditions: the destination lies outside the focal apex’s ordinary internal coercive command (𝑃 +); the actor has practically relevant knowledge of that destination (𝐾+); and the actor retains an actor-controlled first move toward or into it at the focal moment (𝑀+). Receiver acceptance, later asylum, pardon, reinstatement, survival, and realized success are excluded from the primary construct. Historical silence maps to unresolved rather than negative evidence. Two empirical exercises stress-test the measure. A Western Han pilot starts from a pre-specified 26-commander universe, identifies fourteen serious Han-apex setback episodes, and evaluates 192 actor-node uses. Three actor-times are OPTION-IDENTIFIED, with four positive node codes; every positive occurs among active frontier commanders vis-à-vis current adversaries or targets. A second exercise constructs a source-bounded registry of 24 senior Qin actors in 338–251 BCE. Only one case yields a usable serious-setback decision window: the detention of Mengchang Jun at the Qin court. Outcome-blind node enumeration identifies thirteen structurally external political nodes, all coded 𝑃+. The actor has direct practical knowledge of Qi, but the surviving evidence does not establish a Qi-directed or other external first move while detention is active; all thirteen 𝑀, 𝐵, and 𝐶 cells remain unresolved. The result is methodological rather than causal. The Western Han exercise recovers a narrow battlefield-redirection form of exit capacity; the Qin court stress test shows that a dense external political topology does not itself establish actor-controlled initiability. The paper therefore offers a reproducible measurement foundation for historical exit choice sets. It does not estimate a fragmentation effect and does not address downstream outcomes such as talent activation or retention.