miko, i believe that even though the US & allies did actually upheld that primary purpose of the UN charter.
The coalition forces didnt go 'around' the UN, it was just a matter of *some* UN members not willing to act on resolutions they put their signatures on when the time came to act.
Hussein was trying to get a nuke program going, and he already had chemical and biological weapons; which are being actively sought by Bin Laden and his likes.
A world war is a war fought on a global scale with massive casualties. dozens or more terrorist organizations seeking to get a hold of nuclear, biological and chemical weapons, each capable of killing more people in 6 months than all those that died in WW2 ; these terrorrist organizations based and in some cases supported by, several countries is in my book, a clear cut case of a world war.
Destroying the source of WMD's and hunting down these organizations before they can strike is the UN's duty as per their charter.