October 1935. Italian columns cross the Mareb river from their colony of Eritrea into an empire the League of Nations lists as a member. Aircraft and mustard gas against rifles and a throne. Addis Ababa falls in May. Haile Selassie goes to Geneva and tells the League that if Ethiopia can be eaten, so can anyone.
Why then
Mussolini wants an African empire to photograph beside the Roman one he recites, and revenge for Adwa. A clash at the wells of Walwal in 1934, on a border nobody had surveyed, gives him a pretext.
What they wanted
Rome is after a colony and a victory that looks like destiny. Selassie asks collective security to mean what it says. London and Paris care more about keeping Italy as a partner against Hitler, and in December their foreign ministers secretly offer Mussolini much of it.
What changed
The deal leaks and Britain's foreign secretary, Hoare, resigns. Sanctions leave out oil. Italy proclaims an empire in May 1936; in March, with the powers looking south, Hitler had marched troops into the Rhineland.
Still argued
Was the League doomed by design, or would an oil embargo have stopped Italy? Mussolini is reported to have told Hitler it would have forced him out within a week; whether Britain and France could have enforced one is the real argument.