Summary and Key Points: It was supposed to be one of the great strategic masterstrokes of the century. Over more than a decade, China dredged up coral and sand to build a chain of artificial island fortresses across the South China Sea — runways, radars, hangars, and harbors, some rivaling Pearl Harbor in scale, all designed to lock the United States and its allies out of the Pacific. But according to one regional analyst, Beijing may have overl…