The problem with that theory - Hammering Assad not only goads Russia (Assad’s biggest ally), but it empowers ISIS - the strongest force in Syria. A Syria without Assad means a Syria WITH the wort kind of Islamic radicals in charge... and they too apparently have chemical weapons (or so it would appear from the history of this civil war).
Any dictator who uses WMDs on their own people is a monster (Saddam was too) - but at what point are we only shuffling the cards, but not actually “fixing” anything.
Russia won’t do crap. They respect strength and use weakness to their advantage.
We won’t get Russia to do anything if we don’t convince them we mean business.
Reagan didn’t end the cold war by letting the Russians roll him.
Mideast and America were better off before Iraq invasion. What we have unleashed cannot go back into the box. "Secular" nations under dictators is preferable to Islamic regimes. The next rulers of Syria will become another enemy of America and breeder and exporter of terror. I hope I am wrong but history shows America has a horrible track record in the region by many administrations.