While not systematically observing through electronic media US foreign policy actions, I've come to my own conclusion that UN serves mainly to further US foreign aims. Did I draw the wrong conclusion? Are there cases where the UN has taken action that helped non US powers achieve foreign policy objectives that the US opposes?
If the UN existed to serve US foreign aims, then why do they have to waste so much time doing things like vetoing sanctions against Israel, and why then refuse to sign onto International bodies and instruments like the World Court or Kyoto?
Has the US tried to further their own interests through the UN? Sure. That's what it is there for. It is a forum to discuss areas of mutual interest by your country, so every county approaches politics from the perspectives of it's own interests. Some countries are more of the mind that their interest is best served by the common good than others, but that is still an expression of what they believe to be their interests.
But it is not a US-centric body by any means, and certainly is not in its service.