Are you saying that there should be a law against a standing office holder losing an election? I hope I'm misunderstanding you. If the voters decide that someone who is serving in an office should not be returned to that office, whether it's president, senator, governor or whatever, then that's what the election is for. Have you never voted against someone who was currently in office?

Both McConnel and Feinstein should have been voted out of office a cycle or two ago, purely on the basis of competency rather than politics.