When Gina Raimondo, the secretary of commerce, left China this week, it marked the end of a three-month diplomatic blitz by the Biden administration to try to stabilize ties with Beijing and arrest a free fall in the relationship that had raised concerns about the risk of conflict. President Biden had bet that high-level dialogue could help manage an escalating rivalry over trade, technology and the status of Taiwan. Secretary of State Antony J. Blinken was the first to make the trip to the Chinese capital in June, followed by Treasury Secretary Janet L. Yellen and the presidential climate envoy,...