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Washington, we are told, is now "pivoting" its energy, resources and attention from the Middle East and Europe to Asia, reflecting a recognition of the increasingly vital importance of that region for future American wealth, security and global influence. Unfortunately, the execution of this shift, and China's response, are combining to deepen mutual suspicions and potentially destabilize the entire area, ending the decade-long stability in Sino-American relations that resulted from a U.S. foreign-policy shift after 9/11.

At that time, Washington moved decisively away from viewing China ominously as a rising "strategic competitor" (to quote George W. Bush) and toward significant levels of Sino-U.S. cooperation in combating terrorism and dealing with a growing array of common...