In the century prior to the UN’s creation, several international treaty organizations such as the International Committee of the Red Cross were formed to ensure protection and assistance for victims of armed conflict and strife.] In 1914, a political assassination in Sarajevo set off a chain of events that led to the outbreak of World War I. As more and more young men were sent down into the trenches, influential voices in the United States and Britain began calling for the establishment of a permanent international body to maintain peace in the postwar world. President Woodrow Wilson became a vocal advocate of this concept, and in 1918 he included a sketch of the international body in his 14-point proposal to end the war. In November 1918, the Central Powers agreed to an armistice to halt the killing in World War I.
Two months later, the Allies met with Germany and Austria-Hungary at Versailles to hammer out formal peace terms. President Wilson wanted peace, but the United Kingdom and France disagreed, forcing harsh war reparations on their former enemies. The League of Nations was approved, and in the summer of 1919 Wilson presented the Treaty of Versailles and the Covenant of the League of Nations to the US Senate for ratification.
On 10 January 1920, the League of Nations formally came into being when the Covenant of the League of Nations, ratified by 42 nations in 1919, took effect. However, at some point the League became ineffective when it failed to act against the Japanese invasion of Manchuria as in February 1933, 40 nations voted for Japan to withdraw from Manchuria but Japan voted against it and walked out of the League instead of withdrawing from Manchuria. It also failed against the Second Italo-Ethiopian War despite trying to talk to Benito Mussolini as he used the time to send an army to Africa, so the League had a plan for Mussolini to just take a part of Ethiopia, but he ignored the League and invaded Ethiopia, the League tried putting sanctions on Italy, but Italy had already conquered Ethiopia and the League had failed. After Italy conquered Ethiopia, Italy and other nations left the league. But all of them realized that it had failed and they began to re-arm as fast as possible. During 1938, Britain and France tried negotiating directly with Hitler but this failed in 1939 when Hitler invaded Czechoslovakia. When war broke out in 1939, the League closed down and its headquarters in Geneva remained empty throughout the war.
Although the United States never joined the League, the country did support its economic and social missions through the work of private philanthropies and by sending representatives to committees.