Fifty nations write a charter to end the kind of war they just fought
What happened
Delegates from fifty nations gathered in San Francisco for two months, working from proposals drafted at Dumbarton Oaks and Yalta, in what organizers called perhaps the largest international gathering in history, with more than 5,000 documents considered across four commissions and twelve technical committees. Every part of the resulting Charter needed a two-thirds majority to pass. The Charter of the United Nations was adopted unanimously on 25 June 1945 and signed the next day; a seat was symbolically left open for Poland, whose new government had not yet been recognized in time to attend, and which signed months later to become one of the 51 original members. The Charter entered into force on 24 October 1945, now celebrated annually as United Nations Day, once China, France, Britain, the Soviet Union, the United States, and a majority of other signatories had ratified it.
Why it matters
Born directly out of the war's devastation and the League of Nations' earlier failure to prevent it, the UN's Security Council structure, five permanent members each holding a veto, was a deliberate attempt to keep the great powers inside the tent rather than repeat the League's fatal flaw of major states simply walking away.
How we know
The Charter's full negotiating history, including the more than 5,000 working documents considered at the conference, was later published in full by the United Nations itself, letting historians trace exactly how each provision was debated and adopted.
Sources
- United Nations. The San Francisco Conference · Reputable sourceun.org · The domain "un.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
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