Hmmm, Thrawn.. that's a toughie... let me think an hour or so..
NO! Wait! I know! How about SC 1441?

Don't like that one? I'm not suprised.
How about if they'd have enforced/put teeth into the various Bosnian resolutions prior to the 1995 NATO airstrikes that were a clear violation of the NATO charter? Had they done so, NATO probably could have maintained its integrity and legality and the killing could/would have been stopped by the UN...... as it should have been.
The problem is that the UN simply won't intervene in a shooting war, civil or otherwise. They will attempt to keep the peace if they can get some sort of ceasefire, but they withdraw if the fighting breaks out again.
Like I said... when the going gets tough, the problem is ugly and civilians are being slaughtered, the UN won't intervene.
Instead, they look to the sonsabeeches that everyone loves to hate; the ones that WILL intervene and WILL use force to stop a slaughter.
There's a time to talk and there's also a time to act. The UN is good for only one of those.
Sorry, that's just the way it is.