With smiles, firm handshakes and warm gestures, Chinese President Xi Jinping and his US counterpart Donald Trump set a cordial, friendly tone before their historic summit. More than an hour and a half later, they emerged from their first face-to-face encounter in six years with the same genial manner. In front of reporters, ahead of the meeting in Busan, South Korea, a grinning Trump predicted the summit would be “very successful”. “He’s a tough negotiator – that’s not good,” he said, before...