The United States presides over the most far-flung imperial system ever established. This thoughful study compares the American Empire to those of the past, finding much can be learned from the fates of the British, Roman, Chinese, Incan, and Aztec empires. Rome, like the U.S., was a military superpower. And just as Rome s armies were stretched thin, so too are America s but Rome s leaders eventually gave up on conquering Scotland. Will the U.S...