There are important lessons to be learned. For the United Kingdom’s next prime minister, it is obvious that flattery and sycophancy are not enough when dealing with Trump. In one cable, Darroch noted that Angela Merkel and Emmanuel Macron were busy distancing themselves from Trump but warned London: “I don’t think we should follow them.” He was wrong. The United Kingdom needs to fight its own corner. Trump respects only power and leverage.

The problem for London, as Araud told me, is that “the U.K. is trapped by Brexit.” Its positions on Iran, climate, and trade are almost identical to those of continental Europe, but it is leaving Europe and so has no natural allies to turn to. The United Kingdom hoped to survive because of the special relationship, but in Trump’s Washington, Araud said, “alliances don’t matter and there is no sentimentality. The past is increasingly irrelevant.” It’s not just Trump. “Americans are not romantic; all that matters is what you are doing.”

Boris Johnson may believe that he gets on with Trump, but when he is in power, he will find that his personal rapport buys him nothing of substance. He needs leverage. He needs to be transactional. He is dealing with a man without honor.