"First, Iran would have to resume work on a bomb, which the National Intelligence Estimate recently said was halted in 2003. Then it would presume that Iran's leaders would be capable of committing indiscriminate mass murder against Jews, Muslims and Christians alike (no nuclear attack on Israel would spare the Palestinians living there and nearby), whereas there is nothing, in Iran's Islamic and national culture or behavior, to support such a presumption.
"Of course, we do have the threat of President Ahmadinejad to 'wipe Israel off the map.' But there are no signs that his bombastic rhetoric is accompanied by policies, intentions, plans or Iranian political support to carry out such a threat. (If Iran does have clear policies, intentions and plans to destroy Israel, then what on earth are Israel's leaders waiting for?)
"Iran's leaders are no angels, but they have hardly been reckless or foolish. It was Saddam Hussein that started the 1980-88 Iran-Iraq War that Iran survived. Iran's calculating policies have greatly strengthened its strategic position since then. Iran has stood by as its most powerful enemy, the U.S., gave it a gift by overthrowing the two regimes in the neighborhood that gave Iran the most difficulty, Saddam and the Taliban.
"Iran would like a nuclear weapon to project its influence, but mainly for deterrence. In a war in which the U.S. backed Iraq, Saddam Hussein's regime killed tens of thousands of Iranians with weapons of mass destruction. Given Iran's carefully calculated foreign policy, it is highly doubtful that Iranian leaders would be unaware that any move to launch a nuclear strike against Israel would result in - or perhaps be preempted by - an Israeli or American nuclear strike on Tehran. There is no reason to think that the deterrence doctrine of Mutual Assured Destruction (MAD) that prevented a nuclear exchange during the Cold War is absent in the calculus of Iranian leaders and policymakers."