The League of Nations aimed to stop wars, improve people’s lives and jobs, encourage disarmament and enforce the Treaty of Versailles.
Judged against these aims, the League was quite successful in the 1920s.
It stopped border disputes turning into wars. In Silesia in 1921 it held a plebiscite and suggested a partition, which stopped a war between Germany and Poland. It arbitrated between Sweden and Finland over the Aaland Islands in 1921 – its investigation showed that the islands belonged to Finland. When the League rejected Turkey’s claim to Mosul, a part of Iraq (a British mandate), Turkey agreed. Finally, when Greece invaded Bulgaria in 1925, the League ordered Greece to withdraw, which it did. The highest point of the League’s work was the Kellogg-Briand Pact of 1928, an Act of the League’s Assembly, supported by 65 nations, which outlawed war.
The League also improved people’s lives. It took 400,000 Prisoners of War home. It set up refugee camps after the 1922 war between Turkey and Greece. The Health Committee worked against leprosy and malaria. The League closed down four Swiss companies which were selling drugs, and attacked slave owners in Burma and Sierra Leone, setting free 200,000 slaves. Finally, its economics experts helped Austria (1922) and Hungary (1923).
These successes, however, are balanced by some failures.
The League sometimes failed to enforce the Treaty of Versailles. In 1920, the Poles captured Vilna (the capital of Lithuania) and refused to withdraw when the League ordered it to; the League could do nothing. And when, in 1923, Lithuania seized Memel, a German port under League control, the League told Lithuania to leave, but the Conference of Ambassadors gave Memel to Lithuania.
The League could not stop wars when powerful nations were involved. Turkey drove the Greeks out of Smyrna in 1922 – all the League could do was agree. France invaded the Ruhr in 1923 when the Germans did not pay reparations; the League was not even consulted. Again, in 1923, after an Italian general named Tellini was murdered in Greece, Italy occupied Corfu. Greece asked the League for help, which ordered Mussolini to leave – but the Conference of Ambassadors overruled the League and forced Greece to pay compensation to Italy. Other treaties such as the Washington Treaty (1921) and the Locarno Pact (1925) are a sign that nations did not think the League could stop wars.
There were other failures. The ILO failed to persuade members countries to adopt a 48-hour week. A disarmament conference in 1923 failed because Britain objected. It took until 1931 to arrange another conference, which was wrecked when Germany demanded equal armaments with Britain and France.
So, the League of Nations was successful in small ways in the 1920s, stopping small wars and improving lives. But it could not defend the Treaty of Versailles, it failed to get disarmament, and it could not persuade powerful countries to stop fighting.