I was born in August 1946; the first UN meetings were held in London in January that year. So the UN and I are the same age—you might say, nonidentical twins. I have followed it from an early age, and I am glad to report that—despite the small scale and limitations of my lifetime efforts—I have done better with my challenges than my twin has in its equal lifetime.
Per the UN itself, the genocides in Rwanda and the Balkans in the 1990s proved “in the worst possible way” that the UN repeatedly failed to prevent this horror, despite being able to do so. It failed to stop and even to recognize earlier genocides in Indonesia (1960s) and Cambodia (1970s) and much more recent ones in Darfur, Iraq and Syria (against the Yazidis), and Myanmar (the Rohingya). The UN rights council refused to discuss China’s ongoing genocide of Uighur Muslims.
The UN’s failure to prevent small wars—more than 200 in its lifetime and mine—speaks for itself; advocates argue that it has prevented World War III, but that is conjectural. Russia vetoed a Security Council resolution condemning its Ukraine invasion, although the General Assembly passed it overwhelmingly. The UN has done good work against hunger and slavery and promoting sustainable development, but has consistently fallen short of its own stated goals. More than 780 million people (and rising) face hunger, and there are more slaves in the world today than ever before in human history.