Black Star Rising

When a mysterious alien spacecraft approaches the Earth and demands to speak with the President of the United States, then destroys a large Pacific island to demonstrate its strength and seriousness, you'd expect the President to talk. Problem is, there is no President - not even a United States. China rules the Americas, and to most people "US" and "USSR" are just quaint abbreviations in historical dictionaries. But the aliens prove unreasonable about accepting substitutes. . .