Slightly different, perhaps even worse crisis of genocide in the 90s leads to the UN establishing an actual military; IOTL it was highly debated after both Kosovo and Rwanda especially if the UN should or not, at the time the strongest position put forward was for the UN to establish a rapid deployment force which would respond to crisis as they happen and attempt to stall and divert as much damage and harm as possible until the rest of the UN apparatus could respond. IIRC it was very much so a US-like setup, with the troops & supplies being from Security Council countries, but the actual order to go being in the hands of the Secretary General. The hope was, afaik, that if the Sec. Gen. sends in the troops early it could prevent or contain a blossoming crisis, and with their men and material on the line the Sec. Council countries would respond quicker and (hopefully better) to such flashpoints. So, more/messier conflicts in the 90s and perhaps the UNRDF comes into existence.
For bonus points; after the start of the *GWOT, the UNRDF is expanded and as a part of general UN reform is transformed into a GDI-esque organization.