In its trade negotiations with China, the U.S. should have all the leverage. It buys far more from China than vice versa, is sole supplier of numerous critical technologies and commands more loyalty from the rest of the world.

But China brings one powerful advantage of its own: clarity of purpose. Though its negotiating priorities change, over the decades its goal has remained the same: moving steadily up the development ladder while remaining a one-party state. The U.S. ban on supplying key inputs to Huawei Technologies Co....