The Galaxy Is A Bad Neighborhood
The U.S. Space Force was in big trouble. Not from the Russians—we'd whipped them years ago, and not from the Japanese; they had quite wisely decided against mounting a serious military presence in space. Even the Chinese weren't a threat for the near term. No, the threat wasn't external at all. The United States itself was turning inward, forgetful of the heritage that had made it great. Soon the Space Force would be called entirely back to Earth, and there would be nothing American in space save for the comsats that had started it all so long ago.
That's when the aliens arrived. Though themselves entirely human, handsome as gods and pacifist to a fault, they bore bad tidings. Following on behind were creatures of an entirely different nature: warlike, ugly as toads, and with nothing but military conquest on their hive mind. Suddenly the United States Space Force had something even worse to worry about than going out of business . . . .