Iran is against Caliphate and China. Both are more serious threats for US in a long run than any ‘countering US hegemony’ by Iran which is more about regional rivalry, not about hull-scale hostility. It means that Iran’s policy is more coincident with long term US interests than of Obama regime’s. Has Iran ever killed Americans in a couple decades? Last time I ‘ve check it was mostly ‘friends’ Saudis and their Sunni butt-buddies ‘freedom-fighters’ who killed.
Not to mention Iran has a fat chance to transform into a really friendly nation, unlike Arab cut-throats.
I, too, don’t see Iran as a big threat; Iran is a serious regional power and a strong national idea built on becoming one pole in a multipolar world. That is not something we cannot live with, even more so since they have a republican form of government rather than dictatorial one.
I also think that Ahmadinejad is a bit touched in the head and can be very irritating because of that.