The U.S. is straight-jacketed in attacking Iran
Lebanon's The Daily Star's commentator N. Janardhan makes a compelling arguement why the US is unlikely to deal militarily with Iran. In conclusion the author states:
The lesson then is that a U.S. attack is never publicized in advance, certainly not if it cannot be legitimized. Though an attack is unlikely, if the U.S. does decide to go after Iran, it will probably be a surprise as well.