不斩来使 / Envoy Killing Taboo

Definition

不斩来使 / Envoy Killing Taboo is the diplomatic norm that treats violence against a recognized messenger as more than injury to an individual: it changes the public justification, trust, and escalation options available to the sending and receiving powers.

Current Synthesis

The current evidence shows three uses and one boundary failure. Zhouji 53 presents Zhang Yi’s protected status as leverage: if Chu kills him, Qin gains a stronger war pretext. Hanji 158 shows Sui He deliberately urging a breach so Ying Bu cannot quietly return to Xiang Yu. Hanji 372-1 adds an interstate escalation case: the Han mission’s misconduct contributes to the dispute, but Dayuan’s killing and robbery of the expelled party turn a failed horse bargain into a crisis of imperial authority and retaliation.

Qinji 112-3 supplies the category boundary. Han Fei’s imprisonment and poisoning become possible when a royal envoy is recoded as an internal loyalty threat. The norm is therefore neither absolute immunity nor proof that the sending state’s later war is proportionate; it is a political constraint whose breach redistributes legitimacy and closes diplomatic options.

Key Claims

• Killing an envoy can turn a private grievance or failed bargain into a public interstate claim.
• The protection depends on recognition of messenger status and weakens when the person is reframed as an internal security threat.
• Stronger states can exploit the norm by treating an envoy’s death as a war pretext even when the underlying dispute has multiple causes.
• A persuader can intentionally induce envoy killing to close a wavering actor’s path back to the former camp.
• Misconduct by an envoy can worsen a crisis without making subsequent killing and robbery diplomatically costless.
• The norm explains escalation mechanics; it does not establish that retaliation is necessary, unlimited, or proportionate.

Evidence

• War-pretext leverage: Zhouji 53 says Qin can benefit if Chu kills Zhang Yi because the death strengthens Qin’s justification for force.
• Deliberate exit closure: Hanji 158 says Sui He publicly exposes Ying Bu’s defection and urges him to kill the Chu envoy, making reconciliation harder.
• Security-recoding boundary: Qinji 112-3 says Li Si frames Han Fei’s royal identity as a loyalty danger before Han Fei is imprisoned and poisoned.
• Failed-bargain escalation: Hanji 372-1 says the Han envoy insults Dayuan and strikes the golden horse, after which Dayuan expels, intercepts, kills, and robs the mission.

Counterevidence & Qualifications

The four sources do not establish a single codified rule with uniform enforcement. Zhang Yi survives, Han Fei dies after security recoding and private poison, Ying Bu’s breach is intentionally engineered, and the Dayuan case follows serious envoy misconduct. These differences show a norm operating through political interpretation rather than automatic law. Hanji 372-1 supports the claim that killing the mission strengthens Han’s rationale, but it does not prove that the later campaigns were proportionate or that Dayuan had no legitimate basis to refuse the horse demand.

What Changed

• Recast the legacy page into the synthesis-v1 structure without changing its preserved source order.
• Added the Dayuan case as a failed-bargain escalation in which envoy misconduct and receiving-state overreaction remain analytically distinct.
• Clarified that norm breach changes legitimacy and options without validating unlimited retaliation.

Related Concepts

• Irreversible Defection Binding / 断路式策反绑定 - envoy killing can deliberately close a target’s return route to the former camp.
• Moralized War Pretext / 道德化战争借口 - norm violation can be converted into a public justification for force.
• 宫廷后门自救 / Court Backchannel Survival - informal palace access helps Zhang Yi survive the hostile court without resolving the underlying norm question.
• Anger-Driven War Decision / 因怒兴师 - adjacent warning that a genuine grievance still requires an attainable and proportionate response.
• 大宛 / Dayuan (Western Han) - polity whose killing of the Han mission turns a failed exchange into a wider interstate crisis.