One day in 1955, the fledgling People's Republic of
China was unhappy about U.S. involvement with Taiwan, the self-governing island that
Beijing considered its territory. "The Chinese people's exercise of their own sovereign rights in liberating their own territory," Zhou wrote, "is entirely a matter of China's internal affairs." He went on to use that wording, "internal affairs," three more times in the letter. Across the decades, from Zhou's relatively ineffectual plea extending to the dramatically different China that exists today, that precise phrase remains an indispensable tool for the Beijing government when challenges — and what it considers bad behavior — arrive from the outside.