Discuss the civil-war limit.

Intervention is dictatorial interference by a state (or group of states) in the affairs of another state — historically armed, modernly any coercive intrusion — aimed at overriding the target's will. The governing rule: the principle of non-intervention — the sovereignty-and-equality corollary: UN Charter Article 2(1) and 2(7) (domestic jurisdiction) + customary law's non- intervention norm, authoritatively stated in the Friendly Relations Declaration (GA Res 2625, 1970) and applied in the ICJ's Nicaragua v. USA (1986): no armed intervention, no support of armed bands/insurgents (the contras case), no coercion of political/economic choice; and effective control as the attribution standard for organized groups (PIL-I Unit 7's companion). The forms to classify: armed intervention (the classic); indirect intervention (support of rebels, mercenaries, propaganda war); political/diplomatic intervention (election interference); economic intervention (coercive strangulation short of blockade — the legality debates); intervention in civil wars (the strictest prohibition area — the Nicaragua line: no arming either side, even the government's opponents' opponents... the asymmetries noted below). The justificatory doctrines' history (the intervention-decades): the Drago doctrine (debt-collection interventions barred — the Venezuela arbitrations); the Roosevelt corollary's abuse; the Calvo clause's private-law answer (PIL-I Unit 7); the Reagan-era "democratic intervention" claims (Grenada 1983); the modern election-interference doctrine.