LIKE QUIZ-SHOW contestants trying to bash the buzzer first, Volodymyr Zelensky, Ukraine’s president, and Binyamin Netanyahu, Israel’s prime minister, raced to congratulate Donald Trump on his victory—though each for very different reasons. The rush by these and other leaders around the globe, such as Emmanuel Macron of France and Lai Ching-te of Taiwan, to ingratiate themselves with America’s next president reveals much about the perils and opportunities they foresee under Mr Trump, whose only constancy in foreign policy is his unpredictability.