Hang on so the fact that for the past few years he was opposing any sort of intervention in Syria (instead you should be focusing on Making America Great Again) and now overnight changes his view because of chemical weapons (gee when did we last hear about WMDs in the Middle East?) doesn't ring any alarm bells or maybe indicate that he's a populist who will say whatever he wants to garner attention and votes?
Regardless, whatever your views on who released chemical weapons and for what reason, a very clear distinction needs to be made between previous US intervention in Syria and this last attack.
The US has been arming rebels but has never directly attacked Syrian forces before, instead attacking IS. The US has now openly attacked Syria as a sovereign nation.
This is yet another case of the US not "technically" being at war, but instead attacking countries, free of any consequence to themselves. It's an imperialistic worldview, and is exactly what created IS in the first place; attacking a sovereign nation with no authority at all, striking because of some WMDs. We have no idea if that air base had anything to do with chemical weapons.
But no, all the other times the US has intervened have gone so well right? Like how you won the Vietnam War, the various Gulf Wars, the war in Afghanistan, the "War on Terror" and so on...