Iran wants a war.Not a full-blown one, which would happen if they closed the Strait of Hormuz, shutting down the flow of oil and provoking international condemnation. But, say, one where they throw out International Atomic Energy Agency inspectors. Such a move would be seen as a deliberate provocation–clear proof that Tehran had decided to head toward weapons grade uranium. If that leads to bombing by the U.S. or Israel or both, the Iranian people would rally around their leaders. “I think there are hardline elements in Tehran that would welcome a military attack,” says Karim Sadjadpour, an Iranian expert at the Carnegie Endowment for International Peace. “It’s a dangerous and unpredictable gamble, but it’s the one thing that could potentially repair the country’s deep internal political fractures and distract from widespread popular disaffection.” It would also be a well-calculated risk: many observers believe that unless an air assault is sustained for weeks and weeks, it would set back the Iranian program only a few months, perhaps two years at most.

Iran underestimates President Obama’s resolve and the U.S. political climate.Let’s face it, the U.S. has drawn dozens of redlines over the past decade and Iran, much like North Korea, has zigzagged all over them with impunity. President George W. Bush seemed to set a new redline every six months that Iran flouted. So far they haven’t tested Obama. But they may think him distracted by the world economy and the presidential election and somehow take this as an opportunity to press forward secretly with enrichment, moving closer to weapons grade uranium. “We don’t know how Iran calculates the pros and cons of getting nukes,” says Michael O’Hanlon, a foreign policy export at the Brookings Institution. “Given our lack of such knowledge, we should be careful about assuming when they might make their next move.” Given what is known about the Iranian program, it is virtually impossible for it to develop an actual bomb by November 2012. But if Iran did manage to press toward weapons grade materiel under the noses of the IAEA inspectors and this was discovered, then the consequences might be severe. Given his strident statements on Iran (and the bellicose GOP candidates watching his moves), Obama could never allow Iran to get that close to a bomb on his watch without taking action.