“outside of the USA, the UN is actually a well respected and often well liked organisation”

This is a good point, Americans often miss it and don’t like to acknowledge it. A good many of my associates set their ambition to work at UN because UN delivered medicines, clean water and nourishing food to their villages when they were children. That is very far from a bad thing.

“lets also be honest, the UN is often the only entity that can challenge a super power”

Challenge to a debate, maybe, or a chukker of polo. Oh I almost forgot, it’s inconceivable the US could challenge UN in anti-Semitism, not even close. But what other kinds of challenges do you have in mind? The tsunami response? Charitable giving? Effective governance? Rule of law? C’mon, the UN can challenge the US in bureaucracy and precious little else.

“during the first- UN supported Iraq war- 90% of the US military costs were covered by other countries”

Yes, the majority of which support came from Kuwait and Saudi Arabia. UN was not responsible for this support, but the fear of Saddam. Remember Saddam? That nice man who America treated so horribly?