The US rejects the Chinese allegation that these measures are aimed at stifling Chinese development. Like sanctions against the Chinese telecoms giant Huawei and those being considered against social-media app TikTok, this one is being justified under the amorphous guise of national security. The US case rests not on hard evidence but on the presumption of nefarious intent tied to China’s dual-purpose military-civilian fusion. Yet the US struggles with its own security fusion – namely, the fuzzy distinction between America’s under-investment in innovation and the real and imagined threats of Chinese technology. Significantly, Yellen’s speech put both superpowers on the...