Chinese President Xi Jinping’s visit to the White House is not just another ceremonial exchange. It is a test of whether the world’s two largest powers can build trust in an age where mistrust has become the default. Artificial intelligence (AI) is on the agenda. Both sides see danger but have yet to come up with meaningful regulatory cooperation. If this summit fails to deliver workable agreements, the tactical detente could collapse into a new cold war. If the leaders succeed in their personal...