On June 26, 1945, the Charter for the United Nations is signed in San Francisco.
The United Nations was born of perceived necessity, as a means of better arbitrating international conflict and negotiating peace than was provided for by the old League of Nations. The growing Second World War became the real impetus for the United States, Britain, and the Soviet Union to begin formulating the original U.N. Declaration, signed by 26 nations in January 1942, as a formal act of opposition to Germany, Italy, and Japan, the Axis Powers.
But now that the war—at least in the West—was over, negotiating and maintaining the peace was the practical responsibility of the new U.N. Security Council, made up of the United States, Great Britain, France, the Soviet Union, and China. Each would have veto power over the other. A year later, after the war in the East was won as well, Winston Churchill called for the United Nations to employ its Charter in the service of creating a new, united Europe—united in its opposition to communist expansion—East and West. Given the composition of the Security Council, this would prove easier said than done.
My post a year ago today: The Berlin Airlift