The cost will not only be the possibility of hitting Tel Aviv. If Iran is hit, US interests in the Middle East will be hit, Israeli and Jewish interests will/ could be hit as well. If the Gulf of Hormuz is closed then everyone who depends on Oil will be hit. The hatred towards Israel will extend for another 100 years. A caution also includes the note that Saudi oil is significantly located in Shia areas of that country. There is great danger for Saudi as well.
Japan arrests U.S. activist featured in award-winning documentary 'The Cove' (DPA)
from the article: Netanyahu, Obama divided on price of Israeli strike against Iran