Q9: Is Iran developing a covert nuclear weapons capacity? How do we know what we do not know?

No intelligence, Israeli or American, believes there are still undiscovered sites. We would know about any by now. We became aware of the most important Iranian nuclear facilities, including the enrichment facilities at Natanz and Fordo, well before they were put into operation.

Again, the most important question is to compare a negotiated agreement with the absence of an agreement. Any risk of covert facilities is no greater with an agreement than without one. An agreement would increase the on-site inspection and monitoring of Iranian nuclear activities.