Even if we had the capability
I'm not at all convinced that we should be entertaining ideas about intervening in Iran. From what I've read, the religious leadership could well be on the way out. Sure, it'll take time, but Iranian youth appears both very sophisticated and very interested in the freedoms of a liberal society. If we were to do something forceful and foolish concerning Iran we could end up doing terrible damage to a nation evolving on it's own toward a liberal future.