The WSJ has another somewhat dull article on Iran's nuclear weapons program. There's been remarkably little informative discussion.
Iran wants a nuclear weapon and they'll likely get one sooner or later. Many nations would like Iran to get its nuke as far in the future as possible, ideally after a regime change. All the efforts being expended are to delay the acquisition date. The only real question is whether China and Russia will cooperate. That cooperation will depend on a lot of trading and swapping with the US and Europe.
One can argue that Bush's cavalier attitude towards treaties of all types, and the NPT in particular, hasn't helped. I don't have much of an opinion either way. Once Pakistan had its bomb (mostly built pre-Bush), and once the US invaded Iraq, the die was pretty much cast.
All this chatter about treaty obligations etc etc is mostly irrelevant. I can imagine that if China and Russia fully cooperated that Iran's nuclear program could be delayed for a few years, which might just allow for a less whacky Iranian President. (Maybe we'd get a less whacky US president too.)
Update 11/18/06: It looks like Russia is going to block sanctions, so it's pretty much game over now. There's nothing quite like fundamentalist zealots with nuclear weapons. At least Iranian fundamentalists don't seem to have the end-time enthusiasms of our religious extremists.
If Al Gore had been our president, would engagement with Iran have prevented the "election" of their current nut-case president? We'll never know.