During North Korea’s latest military parade, images of its leader Kim Jong-un and his daughter wearing near-identical leather coats have prompted Pyongyang observers to speculate whether the stage is set for the next chapter in the ruling family’s history. For them, the “twin look” is another instance of carefully directed political theatre to burnish the standing of the Kims in the reclusive country for the long term. At the close of the ruling Workers’ Party’s ninth congress on Wednesday...