Trump no longer wants us to be the world’s policeman, just the world’s parents. When someone does something wrong (we are also the world’s judge and jury) then it is up to us to punish them. Not to accomplish anything just to let them know we did not like the behavior, and to let them know there is more of that where that came from. Trump et al think of the bombing as a “time-out”. When a parent gives a child a time-out, there are no repercussions for the parent, so why would anyone expect bombing Syria would have repercussions for the United States.