(19.Dezember 2013) In both its public and private briefings after 21 August, the administration disregarded the available intelligence about al-Nusra’s potential access to sarin and continued to claim that the Assad government was in sole possession of chemical weapons. This was the message conveyed in the various secret briefings that members of Congress received in the days after the attack, when Obama was seeking support for his planned missile offensive against Syrian military installations. One legislator with more than two decades of experience in military affairs told me that he came away from one such briefing persuaded that ‘only the Assad government had sarin and the rebels did not.’ Similarly, following the release of the UN report on 16 September confirming that sarin was used on 21 August, Samantha Power, the US ambassador to the UN, told a press conference: ‘It’s very important to note that only the [Assad] regime possesses sarin, and we have no evidence that the opposition possesses sarin.’

It is not known whether the highly classified reporting on al-Nusra was made available to Power’s office, but her comment was a reflection of the attitude that swept through the administration. ‘The immediate assumption was that Assad had done it,’ the former senior intelligence official told me. ‘The new director of the CIA, [John] Brennan, jumped to that conclusion … drives to the White House and says: “Look at what I’ve got!” It was all verbal; they just waved the bloody shirt.