IRAN AIMING FOR NUCLEAR LATENCY AS DETERRANCE
U.S. has no policy to deal with it

"... Iran (may) choose the course that many government and outside analysts consider likely: Iran could assemble all the major parts it needs for a nuclear weapon — fuel, designs and detonators — but stop just short of assembling a fully operational weapon. In that case, Iran could remain a signatory of the Nuclear Nonproliferation Treaty while becoming what strategists call a “virtual” nuclear weapons state.
http://www.nytimes.com/2010/04/18/world/middleeast/18iran.html?hp

"... Tehran (may) achieve ‘nuclear latency’ (where a country has the ability to construct a nuclear weapon but stops short of doing so), in order to avoid international sanctions and disapproval... (Secretary of Defense) Gates concurs with those analysts... that Iran does not intend actually to build a bomb, but wants the technical know-how to do so as a way of deterring foreign invasions and attacks... Gates sent the White House a memo last January observing that the US has no real developed policy for dealing with Iran should Tehran achieve ‘nuclear latency’..."
http://www.juancole.com/2010/04/gates-worries-about-iranian-nuclear-research-while-khamenei-blasts-us-for-hiroshima.html