The United States is a peculiar sort of empire. Americans have been in what might be called imperial denial since the Spanish-American War of 1898. The U.S. not only denies its imperial ambitions, but shrouds them in a curiously American brand of Christianized liberation theology.
Really, you didn't hear a peep about all those bases? If you don't get the way this country has garrisoned the planet, if you never notice its empire of bases, there is no way to grasp its imperial nature, which perhaps is the point.