Book excerpt: Refuting the conventional wisdom that the end of the Cold War cleared the way for an era of peace and prosperity led solely by the United States, Charles A. Kupchan contends that the next challenge to America’s might is fast emerging. It comes not from the Islamic world or an ascendant China, but from an integrating Europe that is rising as a counterweight to the United States. Decades of strategic partnership across the Atlantic are giving way to renewed geopolitical competition. The waning of U.S. primacy will be expedited by America’s own ambivalence about remaining the globe’s guardian and by the impact of the digital age on the country’s politics and its role in the world. By deftly mining the lessons of history to cast light on the present and future, Kupchan explains how America and the world should prepare for the more complex, more unstable road ahead.