This scenario is exactly what could happen if Israel decides to attack Iran. first and it is scary because Israel will need to be bailed out by America and it will be the end to Israeli "independent" actions going forward or a return to the way things were before when we asked permission. As Benny Morris points out Israel will be hampered by such an attack but not so America. If Iran attacks I just don't see anyway the US will hold back its firepower. America's generals will have a great time displaying their technology. Iran has been doing quite well goading Israel why stop now.
Law expanding definition of terrorist activity passes first Knesset reading (Haaretz)
from the article: The day after Iran's tomorrow