"The Obama administration hoped its support for Syria’s moderate opposition would pressure the regime into negotiations for a coalition government replacing Mr. Assad."

Really???
I don't think so.
What "moderate opposition" was there? The parents of those kids who were tortured for scribbling anti-Assad graffiti? We've known from the start the armed opposition were various radical terrorist factions.

A more logical explanation is the West wanted to destroy Syria with a civil war, just like they've destroyed Afghanistan, Iraq, and Libya with civil wars.