US President Donald Trump has raised serious doubts about the future of the international order established after World War II. In recent speeches and votes at the UN, his administration has sided with Russia, the aggressor who launched a war of conquest against its peaceful neighbor, Ukraine. His threats of tariffs are calling into question long-standing US alliances and the future of the global trading system, and his withdrawal from the Paris climate agreement and the World Health Organization has weakened cooperation on transnational threats.
The appearance of a completely withdrawn, self-centered US has worrying consequences for the world order. It is easy to imagine that Russia would take advantage of such a situation to try to dominate Europe by force or the threat of force. Europe will have to show greater unity and take care of its own defense, although US support will continue to play a significant role.
The prospect of the US withdrawing completely and focusing only on itself suggests dangerous consequences for the world order. It is easy to imagine that Russia would take advantage of the situation and try to establish dominance in Europe by the use of force or the threat of force. Europe will have to show more unity and provide for its own defense, even if reliance on the US will continue to play a significant role. It is also easy to imagine that China would begin to establish itself more actively in Asia, where it openly seeks dominance over neighboring countries. Its neighbors, undoubtedly, already have this in mind and will adjust their moves accordingly.
In fact, all countries will be affected, due to the interconnectedness and relationships between states, but also to large international organizations. The international order relies on a stable distribution of power among states, on norms that influence and legitimize behavior, and on shared institutions. A given international order can evolve gradually without a clear paradigm shift. But if the domestic policies of a dominant power change too radically, then the situation becomes unpredictable.
Since relations between states naturally change over time, the question of order is relative. Before the modern system of states was established, order was often imposed by force or conquest, most often taking the form of regional empires, such as China and Rome (among many others). Variations in war and peace between powerful empires were more a matter of geography than of norms and institutions. Being neighbors, Rome and the Parthian Empire (the area of modern Iran) occasionally went to war, while conflicts between Rome, China, and the Mesoamerican empires never occurred.
And empires depended on hard and soft power. China was united by strong shared norms, highly developed political institutions, and shared economic interests. The same was true of ancient Rome, especially during the Republican period. In post-Roman Europe, the institutions and norms of the papacy and dynastic monarchies were in place, which meant that rulers in certain territories changed frequently due to marriages and family unions, with little regard for the wishes of their subjects. Wars were often fought over dynastic positions, although in the 16th and 17th centuries they were often fought over religious fervor and geopolitical ambitions due to the rise of Protestantism, the schism in the Roman Catholic Church, and increased interstate competition.
In the late 18th century, the French Revolution overturned the norms of monarchy and the traditional constraints on which the European balance of power had long rested. Although Napoleon's imperial ambitions failed after his retreat from Moscow, his armies broke through many territorial boundaries and created new states. This led to the first conscious efforts to form a modern system of government at the Congress of Vienna in 1815.
In the following decades, the Viennese system of the “Concert of Europe” suffered a series of shocks, most notably in 1848, when national revolutions swept the continent. Following these upheavals, Otto von Bismarck launched wars to unify Germany, which would occupy a strong central position in the region, as confirmed by the Congress of Berlin in 1878. Through his alliance with Russia, Bismarck established a stable order until the Kaiser deposed him in 1890.
Then came World War I, followed by the Treaty of Versailles and the League of Nations, the failure of which created the conditions for World War II. The subsequent creation of the United Nations and the Bretton Woods institutions (the World Bank, the International Monetary Fund, and the predecessor to the World Trade Organization) was the most important episode in institution-building in the 20th century. Because America was the dominant player, the era after 1945 has been called the “American Century.” The end of the Cold War in 1991 led to a unipolar distribution of power, allowing for the creation or strengthening of institutions such as the WTO, the International Criminal Court, and the Paris Climate Agreement.
Even before Trump, some analysts believed that this American order was coming to an end. This 21st century has brought a new shift in the distribution of power: it is usually called the rise of Asia, although it is more accurate to say a renaissance. In 1800, Asia had the largest share of the world economy, but it began to lag behind after the industrial revolution in the West. Like other regions, Asia has suffered from the new imperialism, made possible by Western military and communications technologies.
Today, Asia is reclaiming its status as the leading center of global economic production. But its latest successes have come largely from Europe, not the United States. America is not in decline: it still accounts for a quarter of global GDP, just as it did in the 1970s. While China has significantly reduced America’s lead, it has failed to overtake it economically, militarily, or in terms of the number of allies it has.
If the international order is indeed weakening, it is as much a result of US domestic politics as it is of China’s rise. The question is whether we are entering a whole new period of American decline, or whether the Trump administration’s second assault on the institutions and alliances of the “American Century” represents another cyclical decline. We will likely not know the answer until 2029.
The author is a professor emeritus at Harvard University
Copyright: Project Syndicate, 2025. (translation: NR)
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