In the strong-dollar policy¡¯s heyday in the late 1990s, Treasury Secretary Robert Rubin would often be probed for nuance in the doctrine.

He was loath to change; even the smallest deviation or difference of interpretation could cause huge ructions in foreign-exchange markets. Journalists would push on whether prolonged strength furthered American interests. The scrutiny was fair; the former Goldman Sachs boss wasn¡¯t averse to the occasional shift. There were rare instances when it served Washington to allow the dollar to soften or even to sell it. Rubin was aided by a long boom that sucked money into the U.S. Conditions matched the stance. Pragmatism ruled.

Chinese officials today can relate.