While observing the zigzag political manoeuvrings towards, away, and now back again (at least at the time of writing) towards a Donald Trump–Kim Jong-un summit in Singapore on Tuesday, it is worth recalling the words of Dean Acheson, the former United States Secretary of State, who pointed out: “When a chief of state … makes a fumble, the goal line is open behind him.” He might have been talking about goalkeepers in Kiev. But his real point is that the dangers of summitry are not always appreciated by its practitioners.