U.S.-China relations have not been so tense since before President Jimmy Carter and Chinese leader Deng Xiaoping agreed to exchange ambassadors in 1979. Attitudes have hardened especially in the last two months, in part because of the Covid-19 pandemic, and in part because of the troubling developments in Hong Kong. Some voices in the Washington establishment are even advocating a “decoupling” of the deep, complex business connections between the two countries that have been built up over decades.