On Monday the French government released a declassified report summarizing the evidence that it has gathered about three separate chemical weapons attacks on civilian populations in Syria. The report concluded that the two earlier attacks were basically practice runs as the Syrian regime’s adjusted its tactics and objectives away from battlefield objectives and towards raining terror on civilian populations.
http://blogs.scientificamerican.com/...-attack-syria/

I don't believe we should be "punishing" Assad. Our goal should be to make it easier for the opposition to kill him, reducing the chance that the civil war will spill into Lebanon, Turkey, Jordan, Iraq, and Israel, into a war between nations.