It's hard to tell where the beleaguered US administration is in its approach to Iran. According to Richard Heinberg who, for my money, provides some of the best analysis on such matters:
Perhaps the most ominous bits of recent news concern Russia: for the past few weeks that nation has been delaying delivery of nuclear fuel to Iran, and is now withdrawing all 2000 of its technicians at the Bushehr nuclear plant. This is predicated on the excuse that Iran is in arrears on payments for Russian fuel and services, despite the fact that 90 percent of the bills have been paid. Speculation is swirling that Russia, anticipating a near-term US or Israeli air bombardment, is moving its trained personnel out of harm’s way, and minimizing nuclear material on site so as to reduce the release of deadly radiation from the attacks.
Iranian president Mahmoud Ahmadinejad’s March 23 cancellation of an anticipated UN speech also suggests that something is up—but what? Is this a response to political problems back home (his continued tenure as president is far from given), or does it have to do with international relations involving the US, the UK, and Iraq—perhaps knowledge of an impending attack?
So, we are faced with three questions: whether a US air attack on Iran will occur; and, if that is now inevitable, how it will be justified and how it will unfold.