In Arkin’s view, the covid-19 pandemic brought the 9/11 era to an end: two decades of misdirected resources bookended by displays of official incompetence. Arkin argues that the time is overdue to pull back—to close some of our overseas bases and bring home many of the troops. Biden’s decision on Afghanistan can be seen as an attempt to temper some of America’s commitments. What lies ahead, as the chaos engulfing Afghanistan suggests, may not be that peaceful era of political freedom and pluralism which Moyn thinks our militarism blocked, and indeed Moyn’s singular focus on American power may come to seem strikingly insular. We’ve spent decades fighting asymmetrical wars, but now there’s a symmetrical one looming. The United States has never faced an adversary of China’s power: China’s G.D.P. is, by some measures, greater than ours, its active-duty military is larger than ours, and its weapon systems are rapidly expanding. China appears determined to challenge the status quo, not just the territorial one but the scaffolding of international laws that govern much of the world’s diplomatic and economic relations. If two forever wars are finally coming to an end, a new Cold War may await. ♦