Despite the carnage in Gaza, Ukraine and Sudan, and even in the face of the Trump administration’s apparent determination to dismantle what remains of the liberal international order, the human rights attorney Philippe Sands insists he is not giving in to despair. “It’s too early to write off the rules-based system, too early to write off the United States,” he says. “It’s a long game.” Coming from Sands, who has devoted most of his career to trying to contain the darkest human impulses, the cautious pessimism is almost encouraging. He concedes, however, that it does feel as if the lessons...