At the bottom of it all lies a fundamental question- Are we yet willing to admit that our 37 year policy of forcing regime change in Iran has failed & will continue to fail? That they're big enough, smart enough & obviously tough enough to deserve respect if not affection?
If we are, then we must abandon the rhetoric of demonization used to sustain it if we're to do something more constructive. We also need to recognize that the Bush Clan exploited Iran's nuclear program for domestic political purposes as much as anything else. They wove it right in to the Tough On Terrar! fear mongering of post 9/11 propaganda.
It's time for us to turn away from that. If we can forge an agreement, we can assert our position of leadership in a changing world. We just need to make it strong enough to be honored & sweet enough to be accepted by Iran. If we can't accomplish that, it'll erode our leadership position immensely simply because we want more from Iran than the rest of the players. They'll just find ways around sanctions to do business w/ Iran.
Regardless of what we do, other than invade, Iran will likely become the strongest player in the region so we should deal with that rationally. The raving FUD that'll come out of Congress won't be that at all, I suspect.
Repubs intend to allow Obama no victories regardless of the consequences.