Prior to 2016, debates about the global order mostly revolved around its structure and the question of whether the United States should actively lead it or should retrench, pulling back from its alliances and other commitments. But during the past year or two, it became clear that those debates had missed a key point: today’s crucial foreign policy challenges arise less from problems between countries than from domestic politics within them. That is one lesson of the sudden and surprising return of populism to Western countries, a trend that found its most powerful expression last year in the United Kingdom’s decision to leave the EU, or Brexit, and the election of Donald Trump as U.S. president.
It can be hard to pin down the meaning of “populism,” but its crucial identifying mark is the belief that each country has an authentic “people” who are held back by the collusion of foreign forces and self-serving elites at home. A populist leader claims to represent the people and seeks to weaken or destroy institutions such as legislatures, judiciaries, and the press and to cast off external restraints in defense of national sovereignty. Populism comes in a range of ideological flavors. Left-wing populists want to “soak the rich” in the name of equality; right-wing populists want to remove constraints on wealth in the name of growth. Populism is therefore defined not by a particular view of economic distribution but by a faith in strong leaders and a dislike of limits on sovereignty and of powerful institutions.
Such institutions are, of course, key features of the liberal order: think of the UN, the EU, the World Trade Organization (WTO), and major alliances such as NATO. Through them, the Washington-led order encourages multilateral cooperation on issues ranging from security to trade to climate change. Since 1945, the order has helped preserve peace among the great powers. In addition to the order’s other accomplishments, the stability it provides has discouraged countries such as Germany,