In the memo, Mr Gates outlined a scenario - viewed in Washington as increasingly likely - in which Iran would gather all the major parts required to build a nuclear weapon but stop just short of actually assembling them to make a fully operational bomb.
This would mean that Iran could remain a signatory of the Nuclear Non-proliferation Treaty [NPT] while becoming what is sometimes referred to as a "virtual" nuclear weapons state.
Since the three-page memo, written in January, a series of new options have been developed for Mr Obama, including military means for dealing with Tehran if it should acquire a nuclear weapon, the New York Times reported.
According to the newspaper, one senior official described the memo as "a wake-up call" and urged the White House to ponder about how the US could contain Iran if it decided to produce a weapon and how to deal with the possibility that nuclear fuel or weapons could be obtained by a terrorist group supported by Tehran.
http://www.telegraph.co.uk/news/worldnews/northamerica/usa/barackobama/7604292/Gates-warns-Obama-US-lacks-Iran-policy-in-secret-wake-up-call-memo.html
