I don't know what goes on in their office towers in NYC, but having worked for the UN on the ground as a contractor on a number of missions, including the one that was in place as the US began bombing Iraq, one difficulty I observed was trying to mesh groups of soldiers from the far corners of the earth into one cohesive force. And in Iraq, it didn't matter how compliant Saddam Hussein was, and how little WMD we found, Bush was going to bomb the place come hell or high water, so lets not blame the UN for that. Other places (Somalia, Angola, Haiti for instance) may not have achieved the desired goals, but much suffering was relieved by UN efforts during their presence. Such large and complex operations do have the potential to develop glitches, but as another poster said, "let's not throw the baby out with the bathwater".