Yglesias flags the debate about whether to wait for Iran's June presidential election before engaging:
Apparently, the British have one view on the merits of engaging with Iran before the election and the French have a different view. The Americans, meanwhile, disagree with themselves about this. On one level, this is a sort of minor thing to be disagreeing about relative to the big strategic picture. But on another level, it’s hard to get very far with Iran until you make a decision.
But keep in mind there are some people who think it doesn't really matter. A former top aide to a Democrat known for his foreign policy expertise recently emailed me this:
There is a deep-seated, willful desire to substitute hope over experience in dealing with Iran, and we continue to see it play out in the new/old wish for Khatami, the supposed moderate, to defeat Ahmadinejad. What a load of crap. The Clinton admin got sucked into that nonsense and it still persists. When you slap these people and demand the truth, they concede the clerics are in control, and they are master manipulators who have conducted successfully a global disinformation campaign that goes largely unchallenged. Iran has gotten to this point in its nuclear ambitions in part because the rest of the world is divided as to a course of action, and because the west so dishonors its adversaries that it refuses to take at face value the words and actions of those leaders.
I don't consider myself enough of an Iran expert to offer the final word here, but it does seem worth bearing in mind before waiting several more months. Plenty of well-informed people do say that, at the end of the day, the Supreme Ruler is the only one who really matters.