"...but the world without the U.S. in the U.N. would be much worse off."
I doubt that ... must of the "civilized" countries would just leave the UN if we left it first.
What you'd be left with is a U.N. dominated by Russia and China, leading around a pack of bloody dictators... All of them anti-American.
That's a recipe for disaster. As it is, both Russia and China have to build their extra-marital relationships outside the confines of the U.N. and thus their attempts lack the legitimacy that even a reduced U.N. would lend. Given the direction of the EU, much of the so-called civilized socialist countries in Europe will remain part of the U.N., and further tilt the scales against us.
We need to use the U.N., rather than let them use us. For that, we need to keep Republicans in the White House who have a strong disdain of the world body, but also a deep distrust that extends to keeping the U.N. as close as possible so we can check them whenever possible. I don't doubt that Bush knew about the corruption of the Oil for Food program prior to proposing to invade Iraq as part of the WoT. Actually, I'm pretty sure he was briefed on it right after taking office, since Clinton had to have known too.
The U.N. must be kept a close eye on, and that means keeping them where they are so we can ride herd on them. The only problems arise when we elect a foreign policy push over like Clinton or Carter. A simple fact that we're going to have to prevent in the future by supporting the next closest conservative candidate regardless of how much we disagree with him or her.