In light of recent events, it is worth wondering whether there was some hidden wisdom in the old interdiction on British royals marrying American divorcees. And yet Edward VIII, when faced with a choice between the monarchy and the woman he loved, at least chose to abdicate rather than throw the British government into crisis.In the modern day, it is impossible to imagine Meghan Markle showing such grace or dignity. And so an uneven battle is pitched: Markle can appear on television and claim anything she wants, her account accepted uncritically by Oprah Winfrey and most of the American public,...