With the forces of Bashar al Assad having killed tens of thousands of civilians over the past two years, and with persistent rumours that he may use chemical weapons, the world should be grateful to Israel that Syria does not also have a nuclear option.

That is the conclusion of a new book, Tested by Zion: The Bush Administration and the Israeli-Palestinian Conflict, by Elliott Abrams, who served as served as Deputy US National Security Adviser under George W Bush.

Mr Abrams reveals that once the then Mossad director Meir Dagan had provided the US with irrefutable evidence that Syria had a nuclear weapons programme and was building a reactor with North Korean help, only vice- president Dick Cheney thought the US should bomb the site.

Everyone else in the room in Washington that day, June 17, 2007 — Secretary of State Condoleezza Rice, National Security Adviser Stephen Hadley, Defence Secretary Robert Gates, CIA Director Michael Hayden, Director of National Intelligence Mike McConnell, and Joint Chiefs of Staff Chairman Peter Pace, as well as President Bush himself — disagreed.

During a follow-up call, Mr Bush told Israeli Prime Minister Ehud Olmert that the US would go to the UN. Mr Olmert replied: “George, this leaves me surprised and disappointed. Israel cannot live with a Syrian nuclear reactor… We will act.”

Following the call, Mr Bush — while not encouraging Israel to do anything — seems to have implicitly left the military option open to Israel, and all the US officials involved made sure the intelligence information did not leak.

Weeks later, on September 6, Israel destroyed the reactor, although it did not admit to doing so. “The Israelis did not seek, nor did they get, a green or red light from us,” said Mr Abrams.