Obama’s long answer on Syrian chemical weapons was basically a reiteration of what he has said before, until just before the end. He said that, provided it was established that chemical weapons had been used “with some certainty”, he would have to “rethink the range of options”. And this would mean looking at military options available to him at present on the shelf, drawn up at his request by the Pentagon.

This is an incremental shift, a threat to pursue a military option. It still leaves open what kind of options he has in mind: arming the rebels, sending in special forces to secure chemical weapons caches, bombing them, or something else.

It was the bare minimum he could say in the circumstances. He has to try to avoid being seen as weak in failing to respond to Assad so far but at the same time avoid making a firm military commitment. It is playing for time.