The message is firm. Use of chemical weapons is not allowed. It was agreed that if they were used then there would be penalties.
That being said we have enough on our plate. Hell, we have so many guest at our table it is causing a migraine. We have not even told them we can't pay the bill yet.
Let countries within the region who are at greater risk handle it. I under stand how doing nothing makes us look weak. This is just one of those cases where doing nothing makes more sense.
This would be like Russia coming over to handle our borders with Mexico using more effective methods that would be considered inhumane. People would be screaming very quickly for them to get the hell out.
It is an issue where a group of higher powers needs to agree and then snuff out the issue. Whether right or not, one lone outlaw going against the wishes of the rest will cause conflict with them.
From a tactical standpoint if this was a setup it is a very impressive one.