1. Factors of irrationality are not present in the Iranian case at the moment, although that could change. Sometimes domestic leaders are "forced" to go to irrational war due to the demands of the populace, but again, Iranians have demonstrated a weariness of any sort of national struggle.
2. Probably not. Northeast Asia is also a critical area for US foreign policy, and yet we did not deem North Korea's acquisition of the bomb to be an unacceptable development. It's unacceptable up until the moment it happens, at which point it is a fait accompli.
3. Iran's ability to fight proxy wars is limited only to certain terrorist groups, the main of which is Hezbollah. Iran would have to demonstrate a willingness and capability to conduct larger-scale proxy wars than they have. They are not the Soviet Union.
4. Sanctions have to work in tandem with diplomacy, and so far Rouhani has demonstrated a willingness to come to the table that was not present in Ahmadinejad, and this is due to the electoral mandate he received, due in turn to the people's dislike for the sanctions. Sanctions failed in North Korea because it is an undemocratic society that is unconcerned with the people's suffering due to the sanctions. Compromised though they may be, Iran still has competitive elections and a leadership that must be accountable.
5. I had not considered this. I suppose it depends on how the attacks are interpreted, and how popular the country's nuclear program actually is compared to how much of that is just the leadership wanting to be important on the world stage. Would the people consider anti-nuclear strikes to be egregious interference from the West or would they quietly breathe a sigh of relief?
Monster Hunter: pissing me off since 2010.