James Jeffrey: “The U.S. was slow countering ISIS's rise, and we didn't react as quickly to events in Syria.”

He has shown little willingness to be flexible on any issue, and at the moment may be concluding that it is better to sit on a pile of rubble with half his population and 60 percent of his country than to compromise.

If the regime and its sponsors do not accept this path forward, we, aligned with much of the international community, will continue the very broad economic and diplomatic pressure on this regime.

This regime has used chemical weapons repeatedly.

If we do not play the kind of very costly and at times very difficult role that we play in the world, then you get a Syria; you get a law of the jungle in a very important area where you do have, as I said, five armies.