Illustrate with the League-to-UN transition.

The criteria — the Montevideo Convention, 1933, Article 1: (1) a permanent population; (2) a defined territory; (3) a government (effective control); (4) the capacity to enter into relations with other states (independence). The refinements (Unit 3's fuller treatment): effectiveness vs. legality — illegal origins (aggression, apartheid) taint statehood (ex injuria jus non oritur: Rhodesia's UDI, Crimea 2014); self-determination as the modern title's source; failing states' stress cases; and the declaratory/constitutive recognition theories (Unit 4). Why statehood matters here: statehood's changes — births, deaths, mergers, break-ups, territorial transfers — are succession's occasions. Nepal: the continuing state par excellence — no succession event since the 19th-century boundary settlements.