His final two paragraphs note that Al-Nusra rebels may be the only group left with access to sarin in Syria soon:
The administration’s distortion of the facts surrounding the sarin attack raises an unavoidable question: do we have the whole story of Obama’s willingness to walk away from his ‘red line’ threat to bomb Syria? He had claimed to have an iron-clad case but suddenly agreed to take the issue to Congress, and later to accept Assad’s offer to relinquish his chemical weapons. It appears possible that at some point he was directly confronted with contradictory information: evidence strong enough to persuade him to cancel his attack plan, and take the criticism sure to come from Republicans
The UN resolution, which was adopted on 27 September by the Security Council, dealt indirectly with the notion that rebel forces such as al-Nusra would also be obliged to disarm: ‘no party in Syria should use, develop, produce, acquire, stockpile, retain or transfer [chemical] weapons.’ The resolution also calls for the immediate notification of the Security Council in the event that any ‘non-state actors’ acquire chemical weapons. No group was cited by name. While the Syrian regime continues the process of eliminating its chemical arsenal, the irony is that, after Assad’s stockpile of precursor agents is destroyed, al-Nusra and its Islamist allies could end up as the only faction inside Syria with access to the ingredients that can create sarin, a strategic weapon that would be unlike any other in the war zone. There may be more to negotiate.