President Obama would be crazy not to dive deep into diplomacy with Iran, right now. Forget the standard throat-clearing bromides and water-testing toe-dips that mark the resumption of relations with suspect characters. When the world's leaders meet at the U.N. General Assembly next week, Obama should not only shake hands with Iranian President Hassan Rouhani but also meet with him privately, hand him a list of a dozen issues to discuss (uranium enrichment, sanctions, regional stability, etc.), and even be prepared to announce, if possible, a time and place for negotiations to begin and a roster of the delegates to be invited.
If Rouhani is who he claims to be—an Iranian moderate who has the authority to strike a bargain on nuclear programs and economic sanctions (at least until hardliners lose patience with him)—then this is an opportunity no Western leader can pass up.
If it's all a ruse, or if the mullahs overrule whatever deal emerges, there's no harm in trying. In fact, if things go bad and Western leaders feel compelled to respond with tighter sanctions or military action, they could do so with greater legitimacy after having given the high road a chance.
In any case, it does little good to sit around and debate the potential truth of Rouhani's proclamations or the nature of Iranian politics, about which any outsider's knowledge is limited. Rouhani has put his statements on the table. No Iranian president, in the entire revolutionary period, has said anything remotely this appealing. He has appointed, in Mohammad Javad Zarif, a foreign minister whose known views are consistent with these statements. Iran's economy is in such a tailspin that the regime—including the mullahs who are ultimately in charge—may be willing to trade some things of value for an end to the U.S.-imposed sanctions.