What could justify military action against Iran? Under international law, governments have the right to take military action to repel an armed attack and to preempt a certain and imminent attack. But the United States has not been attacked by Iran, and is clearly not in any imminent danger of armed attack. [. . .] Setting aside the sensationalist rhetoric of Iranian leaders, any realistic look at the Middle East and Iran must conclude that Iran’s military activities are primarily driven by fear and designed to preserve the regime. [. . .] The voluntary suspension of uranium enrichment by the Iranian government will only yield lasting results, however, if it is a part of a broad set of initiatives that guarantee security, peace, and economic development in Iran and the Middle East. Unilateral action against Iran in the absence of an overall plan for regional peace and security will be seen by most of the people of the region as aimed at safeguarding Israel’s supremacy and imposing an unjust peace on Palestinians and the broader Muslim world.
See also this account of a Norman Podhoretz book reading at a Barnes & Noble: "a lady stood to say that she had over a hundred relatives in Iran: Why do you want to kill them?!" Basically, Iranians aren't enthusiastic about the prospect of their country being attacked by the United States of America and this sentiments seems to hold more-or-less entirely across the Iranian political spectrum. Which, of course, is about what you'd expect given that Iran is a country populated by human beings. But if you'd like to unite the population of Iran around the only national government it's got, and push its regime toward firmer alliance with whichever enemies of the United States it can find, then war sounds like a great option.