where does the Bible call out the UN and in why aspect has it been successful? Cold War? Vietnam, Korea, China? Yugoslavia? Seriously, where has the UN helped anything?
The Bible does not call out the UN 'per say'.
The Scriptures give the prophecies and then it is up to the Bible believing folk (as foolish as they may be) to look at what seems to fit based in the world that is happening/and entities that exist.
The UN fits in this regard.
Biblically speaking the UN is successful in that it was created in 1945 and has been growing with more structures put in place (The WHO, etc.) over the years waiting to be empowered.
The UN was never Biblically meant to solve/help what you mentioned. In fact, they have done the opposite and created wars, as they were supposed to.
They are under the guise of supposed to have worked for peace through the years. That was only to keep them existing through these years. But their true purpose is to be an OWG. From the Bibles view, the 8th king. It will take WW3 to implement that. (Order through chaos.) This is God's purpose, for the 8th king to serve as the 'hour of judgment' from him.