The United States was not always the world’s economic leader. History looks more like a long-distance race in which one county assumes leadership for some time, only to lose it to another and return to the pack or disappear from sight. For much of the first millennium, and until the fifteenth century, China probably had the world’s highest level of output per capita. For a couple of centuries, leadership moved to the cities of northern Italy. It was then assumed by the Netherlands until around 1820, and then by the United Kingdom from 1820 to around 1870. Since then, the United States has been in the lead… If history is any guide, the United States will not remain in the lead forever. –Oliver Blanchard