America at 250 presents one of the strangest paradoxes in modern history. No democracy has accumulated greater economic, military, technological, and cultural power. Few are less content. The anniversary — in marked contrast even to the Bicentennial, despite troubles in those times as well — is being celebrated amid a hurricane of angst and anger.

It can seem perplexing, because the United States remains the world’s largest economy, the dominant military power, home to an astonishing disproportion of the world’s most valuable companies and highest-ranked universities, and the principal exporter of global popular culture. American music, films, software, financial markets, and scientific research influence billions of people far beyond its borders. By almost every conventional measure of national success, America rocks.