When President-elect Donald Trump took the congratulatory telephone call from Taiwan’s President Tsai Ing-wen on December 2, he violated a strict protocol that had been in place for more than three decades. Since the United States switched its diplomatic recognition from the Republic of China (the official name of the noncommunist remnant based on Taiwan) to the communist regime in Beijing in 1979, there has been no official contact between the U.S. and Taiwanese presidents. Not even staunchly pro-Taiwanese American leaders, such as Ronald Reagan and George W. Bush, thought it worth angering Beijing merely to pursue enhanced ties with Taipei.

Since the phone call, Trump has taken several other actions that have produced a dangerous chill in U.S.-China relations. Most notably, he appears to be challenging the foundation of that relationship, the fuzzy but very real “One China” policy. In so doing, Trump not only risks getting his administration off to a terrible start with a major trading partner and foreign creditor, but he has created the conditions for an exceptionally dangerous security crisis in East Asia.
Taiwan has long been a sore point with Chinese leaders. In their view, Taiwan was (and remains) a Chinese province that Japan stole from China following a war and an imposed treaty in 1895. The United States, according to that narrative, then prevented reunification following the Communist victory on the mainland in 1949, when President Harry Truman deployed the Seventh Fleet in the Taiwan Strait to thwart an invasion of Taiwan. To Chinese leaders, and apparently to most mainlanders, the restoration of Chinese sovereignty over Taiwan remains unfinished business.