Can't see it happening MArk.... The US will have a hard enough time persuading it's allies there's a valid reason to attack. Iran's Ahmedinijad has just been on a charm offensive at the UN in New York, saying that they don't need nuclear weapons, just nuclear power...and considering they've taken this long to get the 4% enrichment to achieve nuclear power for heat/light, it could take them decades to get the over 80% required for nuclear fission... I think the argument is whether Iran should be allowed self-determination to have their own nucear capablilty without the US's intervention.... it's obvious the US don't want this to happen.
It will probably be the same old routine. Major terrorist attack > Blame it on a country with no evidence > Scare people > Attack country and get oil.
So I wait for the next terrorist attack that will give America an excuse to attack Iran.