Defense Sec. Panetta gave 3 reasons why Israel should not attack Iran.
1-It will harm world economy
2-It will only impede the Iranian nuclear effort 2-3 years
3-there may be unexpected conequences
Whether an attack would harm the economy is not a given.If he refers to oil supplies,then the US has plenty of ability over the short and long run to correct the problem.
Open up ANWAR in Alaska,allow drilling in the Gulf of Mexico.encourage fracking,and approve the Canadian oil pipeline.
Even if it only stops the Iranians for a limited number of years,that represents a period without a nuclear Iran hanging over Israel.Who knows what will happen in 3 years? Perhaps there will be a new Iranian Govt? or a new US President with a backbone? Or Israel might have to attack again?
Why worry only about the world,when from the point of view of Israel, there is an existential threat to its existance.
Yes there can be unexpected consequences if Israel attacks-but there may be unexpected consequences if Iran obtains the bomb,and either uses it or threatens its region.