One [of the problems] is the ambiguity about what rights the Iranians will have to continue nuclear research and development. They are working on centrifuges up to 20 times faster than today’s, which they want to start deploying when the agreement’s [the currently negotiated agreement between Iran and United States/Europe] first ten years are up. The worry is that better centrifuges reduce the size of the clandestine enrichment facilities that Iran would need to build if it were intent on escaping the agreement’s strictures.
That leads to the issue on which everything else will eventually hinge. Iran has a long history of lying about its nuclear programme. It only declared its two enrichment facilities, Natanz and Fordow, after Western intelligence agencies found out about them. A highly intrusive inspection and verification regime is thus essential, and it would have to continue long after other elements of an agreement expire. Inspectors from the IAEA would have to be able to inspect any facility, declared or otherwise, civil or military, on demand…
For a deal to be done in June 2015, Iran will have to consent to an [intrusive] inspection regime. It will also have to answer about a dozen questions already posed by the IAEA about the “possible military dimensions” of its nuclear programme. Yet on March 23, 2015Yukiya Amano, the agency’s director, said that Iran had replied to only one of those questions. Parchin, a military base which the IAEA believes may have been used for testing the high-explosive fuses that are needed to implode, and thus set off, the uranium or plutonium at the core of a bomb, remains out of bounds. Nor has the IAEA been given access to Mohsen Fakhrizadeh, the physicist and Revolutionary Guard officer alleged to be at the heart of the weapons development research. The IAEA’s February 19, 2015 report on Iran stated that it “remains concerned about the possible existence…of undisclosed nuclear-related activities…including activities related to the development of a nuclear payload for a missile.”
Excerpts from, The Iran Nuclear Talks: Not Yet the Real Deal, Economist, Apr. 4, 2015, at 43