In the context of the 1930s when getting an army to the other side of the world was no easy task, the League had something of an excuse where Manchuria was concerned (though not with regard to sanctions). But Abyssinia was another matter. Quite simply it dealt the death blow to the League of Nations:
Collective security failed, a weak power was virtually left to the mercy of a major power
The League lost all credibility as a peace keeping force
Like Japan, Italy was a permanent member of the League’s Council
First, the Hoare-Laval Pact showed the depths to which politicians would go in Britain and France to avoid war
And when Britain and France were forced into acting against Italy, it quickly led to the end of the Stresa Front
It also gave Hitler the opportunity to re-militarise the Rhineland