As for Assad, no evidence exists that he is the guilty party. Stephen Cohn just stated this on CNN. Of course, others on CNN jumped all over him. There is a push to get us into a war with Russia, led by McCain.
Taking out Saddam was not the mistake. Taking out Saddam and not following through with a post WWII European occupation for the next 25 years was the mistake. And apparently we no longer have the fortitude for that.
Changing the Mideast culture to one that is western friendly will take at least a generation. Obama cut and ran the second he took office. He left the void that Tehran and ISIS have filled. As long as we have this wishy washy electorate, we cant make any long term commitments that allies can rely on. The best we can do is contain the problem in the ME.