[quote=@Pepperm1nts]
Maybe Assad really is that dumb, but Syria is currently a big clusterfuck and I'm not entirely convinced. There are a dozen other factions vying for control that could have been the ones to deploy the gas, that would make far more sense than Assad just randomly deciding he wants to spice his life up a bit by pissing off the US. 
[/quote]

I'm not saying I know for certain it was him, i'm just saying that it isn't surprising or out of character for a dictator to do something like that. He figures he has Russian protection and that the current US President is weak. Throw that in with the personality of somebody who has had that level of power for so long and you have a good recipe for a gas attack