The Assad regime in Syria is reprehensible. The use of chemical weapons by any actor is unacceptable. Violence as a tool to effect political change is a monstrosity. All of these things are true, but none justify the United States taking the role of an avenging god.
By a limited definition of Article II, the president can act on the spot in an emergency to protect American interests. That authority is still not, in my opinion, a blanket permission to act unilaterally in Syria.
The United States is once again on the brink of war in the heart of the Middle East. While the necessity of some kind of military intervention -- if only symbolic in nature -- is now evident, the risks are enormous.
From subtle suggestions to diversionary rhetoric to preemptive flourishes, there is, save for Bill Clinton, no other president of the modern era better adapted to the art and science of influence and strategy.