Anyone studying the United States understands its concern with nuclear weapons. Throughout the Cold War it lived in the shadow of a Soviet first strike. The Bush administration used the possibility of an Iraqi nuclear program to rally domestic support for the invasion. When the Soviets and the Chinese attained nuclear weapons, the American response bordered on panic. The United States simultaneously became more cautious in its approach to those countries.
In looking at North Korea, the Iranians recognized a pattern they could use to their advantage. Regime survival in North Korea, a country of little consequence, was uncertain in the 1990s. When it undertook a nuclear program, however, the United States focused heavily on North Korea, simultaneously becoming more cautious in its approach to the north. Tremendous diplomatic activity and periodic aid was brought to bear to limit North Korea's program. From the North Korean point of view, actually acquiring deliverable nuclear weapons was not the point; North Korea was not a major power like China and Russia, and a miscalculation on Pyongyang's part could lead to more U.S. aggression. Rather, the process of developing nuclear weapons itself inflated North Korea's importance while inducing the United States to offer incentives or impose relatively ineffective economic sanctions (and thereby avoiding more dangerous military action). North Korea became a centerpiece of U.S. concern while the United States avoided actions that might destabilize North Korea and shake loose the weapons the north might have.
The North Koreans knew that having a deliverable weapon would prove dangerous, but that having a weapons program gave them leverage -- a lesson the Iranians learned well. From the Iranians' point of view, a nuclear program causes the United States simultaneously to take them more seriously and to increase its caution while dealing with them. At present, the United States leads a group of countries with varying degrees of enthusiasm for imposing sanctions that might cause some economic pain to Iran, but give the United States a pretext not to undertake the military action Iran really fears and that the United States does not want to take.
Israel, however, must take a different view of Iran's weapons program. While not a threat to the United States, the program may threaten Israel. The Israelis' problem is that they must trust their intelligence on the level of development of Iran's weapons. The United States can afford a miscalculation; Israel might not be able to afford it. This lack of certainty makes Israel unpredictable. From the Iranian point of view, however, an Israeli attack might be welcome.
Iran does not have nuclear weapons and may be following the North Korean strategy of never developing deliverable weapons. If they did, however, and the Israelis attacked and destroyed them, the Iranians would be as they were before acquiring nuclear weapons. But if the Israelis attacked and failed to destroy them, the Iranians would emerge stronger. The Iranians could retaliate by taking action in the Strait of Hormuz. The United States, which ultimately is the guarantor of the global maritime flow of oil, might engage Iran militarily. Or it might enter into negotiations with Iran to guarantee the flow. An Israeli attack, whether successful or unsuccessful, would set the stage for Iranian actions that would threaten the global economy, paint Israel as the villain, and result in the United States being forced by European and Asian powers to guarantee the flow of oil with diplomatic concessions rather than military action. An attack by Israel, successful or unsuccessful, would cost Iran little and create substantial opportunities. In my view, the Iranians want a program, not a weapon, but having the Israelis attack the program would suit Iran's interests quite nicely.