Iran's nuclear weapons ambitions are ominous in light of its hostile foreign policy and longstanding support for terrorism. But Iran's repeated threats to annihilate the state of Israel while it develops the world's most dangerous weapons have created an even more explosive situation. If diplomatic efforts to defuse the situation fail, Israel may see no other choice than to launch a preventive strike against Iran's nuclear facilities. This paper maps out the likely results of an Israeli attack, outlines Iran's probable reaction, and explains why it is now crucial that the Obama Administration take action to mitigate and defend against Iran's response to an Israeli strike.