My take on that - he has decided on inaction but needs the congress to save him from his "chemical weapons are a red line" remark from an year ago.
I am not sure if there is any salvage of the Middle East situation right now - there are generational grudges and hatreds to unfold there. I don't think that there are good moves on that board. The pessimist in me just wonders whether the firewall should be on Bulgaria/Greece border or on the Bosphorus.
Disclaimer - I live in Bulgaria for now.