To what extent was the League of Nations a success?

Do not conflate the League's commissions — the ILO (improving labour standards worldwide), Health Committee (combating disease and drug trafficking), Refugees Committee (resettling displaced persons after WWI), and Slavery Commission (working to abolish the slave trade) are four entirely separate bodies with distinct functions and achievements. Name the specific body and its specific outcome to score Level 3+. A vague reference to 'a League committee' cannot rise above Level 2.

Balance across both decades — don't only write about the 1930s — the majority of answers focus exclusively on failures. A Level 5 answer must address genuine 1920s successes (Aaland Islands 1921, Upper Silesia 1921, Greek–Bulgarian border 1925, humanitarian work) AND 1930s failures (Manchuria 1931–33, Abyssinia 1935–36), then explain WHY the 1930s were harder: the Depression, the permanent absence of the USA, and Britain and France prioritising national interest over collective security.

Analyse each case — don't list it — for every success or failure, explain WHY it matters. Don't just state 'the Manchurian Crisis was a failure' — explain that Japan faced no military response because Britain and France were unwilling to risk war in the Far East, demonstrating that collective security only functioned when the cost to members was low. That analysis is what separates Level 3 from Level 4–5.