How about that for a message?
Whatever the President does, even if he does nothing regarding Syria, it is going to be wrong and eventually to be considered immoral. So should he do what might be considered less immoral or do whatever he thinks is right, disregarding the gradation of immorality?
Within this domestic and international political environment, he can take whatever action he believes best to take. It will be challenged in the future, anyway.
I would warn Assad to leave office immediately and agree to a transitional and temporary head of government or face the possibility of death. If he did not do this within 2 days, then the U.S. should find his location and send drones after him until he is either proven dead or has left the country.
If there’s a message to be sent, this is the kind that is usually sent during conditions of revolution or likelihood of war. Are there any other suggestions?
Harry Truman had atomic bombs and his use of them ended the war with Japan.
President Barack Obama has drones.
Photos of Assad’s name on a few drones might support the message. If that doesn’t work, send the drones. No need for boots on the ground or anywhere. Tie a few boots onto the drones. Obama doesn’t have to prove that he will use drones, nor that he will get after immoral leaders anywhere, boots or no boots.