*Okay...so Donald Trump says Assad is no big deal and can stay, Assad then drops chemical weapons on his people and Trump says it's Obamas fault....WTF. Does this guy just pick anyone he can think of to blame for whatever happens on his watch?
Perhaps your memory is failing or selective, Obama stupidly asked congress for approval of military action and was refused after Allies would not do so as well. If he had simply gone in everyone would be complaining that he did at this point...damned if you do or don't I suppose.