it was Neville Chamberlain, and what is going on if we stay out is not appeasement. and Syria was a french colony, that is why they are mildly involved, and probably partly why the UK doesn't give a shit.
the domino theory, of if we don't bomb the crap out of them that it will embolden N. Korea, iran, etc. is a rehash of the Neville Chamberlain type argument used to go into viet nam. that if we did't stop them, the whole world will go domino theory and communism would expand everywhere. it didn't, but not because we went into the vietnamese civil war.
bombing the hell out of their program has a very uncertain outcome... did you know that Assad has some ship-destroying missiles given to them by russia? do you think that the image of one of our destroyers sinking would not expand the punitive action? would the authorization from congress include expansion into a regional war or possibly further?