It is unlikely that George Bush will committ himself to attacking Iran at this point when he will not be in office to see the job through.It is also unlikely that President Bush trusts Hussein Obama to handle the aftermath should he become President.
Israel,has catagorically stated that it will attack Irans atomic weapons sites before the end of the year if the programme is not halted.Israel will be fearful of the opposition from the USA should Obama reach the oval office.
For these reasons,I believe,Israel will be the first to attack Iran.
Of course I believe ,air and missile strikes to neutralize the nuclear capability of any despotic,belligerent regime could be only positive.
There will, be some repercussions including a temporary rise in the cost of crude and a knee jerk spike in terrorist activity.
Howevber,the long term prognosis is actually a reduction in the cost of crude as the threat of nuclear strikes tails off.With Iran promptly defeated,a regime change will shortly follow with a sharp drop in global terror attacks soon after.