Well, if you're going to be technical, the president isn't supposed to do anything except in emergencies. He is JUST supposed the sign, or veto what Congress did. So none of what Trump is being blamed/credited for can actually be pinned on him. (Same with Obama and all previous presidents). Unless you are crediting their leadership and Influence, in which case the president's do get credit/blame for things like constitutional amendments that were passed under their leadership.