For a regime that is all about spin and image management, the admission that the concerns of the international community were not misplaced, and the consequent gutting of its nuclear narrative would be a devastating blow. And it would make a deal even harder to reach—though it is hard to imagine a credible, sustainable deal without resolution of this issue. For any deal that overlooks Iranian stonewalling about the past will only encourage further Iranian stonewalling in the future.

Conclusions. For all these reasons, it will be difficult to square with Iran the requirements of a credible, sustainable agreement—forthrightness regarding past nuclear activities, real transparency concerning current and future activities, and meaningful limits on enrichment and reprocessing—with the Islamic Republic’s goal of confirming its status as a nuclear threshold state, while preserving a degree of ambiguity regarding its capabilities. And it will take more than “heroic flexibility” (to use Ayatollah Khamenei’s phrase) to obtain such an agreement. Rather, it will require nothing less than for Iran to truly embrace the goal of nuclear energy for peaceful purposes, by confirming its declaratory commitment to this goal with deeds to match. That would truly be change to believe in.

Michael Eisenstadt is a senior fellow and director of the Military and Security Studies Program at The Washington Institute for Near East Policy.