I was attending a web chat with Ambassador James F. Jeffrey regarding the US policy toward Iran; sadly there were not many people from Iran. I strongly recommend reading the content of these links before going on.
It is obvious that Iran and the US are standing face to face because of different interests they have in the region, which includes, but is not limited to, making nuclear bombs, their policy toward Israel and interference in Iraq. Now what will be the policy of the US toward Iran?
It looks like the US is not considering a complete war with Iran in its options.
It also looks like the pressure from the occupation of Afghanistan and Iraq on the Iran's government has led to more power for anti-American political forces in Iran.
So, now I think the remaining options are:
The second option is also already tried. You may have read about the news of the bombing in Khuzestan, and the riots for a cartoon in Azerbaijan. The regime shows a high degree of capability and power for dealing with such matters, so I think this option is also off the table.
The third option (using special-force operations in different parts of Iran for destroying various facilities) is nearly impossible. As you might remember, the first of such operations by delta forces to rescue the American hostages failed in Tabas. I don't think that the US politicians take the risks again. Aerial bombing using stealth fighter bombers may look like a good idea, but since most of Iran's strategic nuclear and military facilities are about a kilometer deep under mountains, it is totally useless and this would most likely destroy the economical infrastructure supporting the country instead. I guess Iran's obvious reaction will be to increase the number of attacks toward American forces in the region and to stage dealier attacks against Israel. This will be even more effective now, after the latest Arab-Israeli conflict. It could be even deadlier in terms of the number of civilian casualties. I am sure that American politicians will avoid such a conflict in favor of Israel.
I think the fourth option is becoming impossible more and more. In the first days after revolution the US was full of Iranian opposition members, and under their influence the US politicians underestimated the number of people who are in favor of the current government because of their religious background. Years of armed fighting by the Mojahedin, Toodeh and other political parties and the Noje coup d'ťtat has shown that this government cannot be changed that easily!
I think now Americans need a new innovative idea, not yet used in their history. The increase in the budget toward Iran indicates they have come up with one, but what is it? Is it some thing bloodier than the above solution?
I hope that the new solution is spending that money on educating the next generation of Iranian politicians about realities in the new world.