Last week, China got what it has been wanting since the Biden administration arrived in office: a visit by the U.S. official best positioned and most inclined to make the economic concessions it seeks, Treasury Secretary Janet Yellen. If Beijing had had its way with Washington, Yellen would have been welcomed there months ago, before the spy balloon incident and before the planned February visit by Secretary of State Antony Blinken that was cancelled because of it. The Chinese would have preferred wheeling and dealing with Yellen on trade and tariff issues rather than being hectored by Blinken on human...