During the Cold War, the United States and the Soviet Union implicitly split responsibility for maintaining order in much of the world. From the middle of Germany east to the Pacific coast of North Korea, Moscow made sure its communist clients didn't trouble the rest of the world. Regarding this broad slice of Eurasia, the United States paid little more than occasional rhetorical attention. The Kremlin crushed uprisings in Hungary in 1956 and Czechoslovakia in 1968, and Washington merely tut-tutted. The Communist government of China starved millions in the 1950s and 1960s and America hardly noticed; Beijing banished millions more to the countryside and re-education camps during the Cultural Revolution of the 1960s and 1970s, and the United States lifted not a finger to prevent it.
Meanwhile America had its way in western Europe, the western hemisphere and most of the Pacific. Generally speaking, America exercised its influence in a less heavy-handed way than the Soviet Union did. The Marshall Plan kept western Europe friendly. American troops no longer invaded Latin American republics, as they had earlier in the century. American meddling tended to be discreet, as when the CIA toppled a left-leaning regime in Guatemala in 1954.
The exceptions tended to prove the rule. An American outpost in South Korea was held at great cost. An American outpost in South Vietnam was lost at great cost. A Soviet beachhead in Cuba nearly precipitated a nuclear war.
Beyond these two exclusionary zones, in what in the 1950s and 1960s was called the Third World, the superpowers competed for influence but without risking general war. The Middle East, South Asia and Africa were largely allowed to settle their problems themselves.
The demise of the Soviet Union in the early 1990s brought an end to this system of two cops on two beats. It was replaced, imperfectly and after some hesitation, by a system of one cop on one beat—the one cop being America and the one beat being the whole world. During the Cold War the United States would not have fought two wars against Iraq, lest the fighting provoke a Soviet response more dangerous than the Iraqi threat. The United States would never have invaded Afghanistan and occupied it for two decades, not least because during the Cold War the Soviet Union would never have allowed Afghanistan to become a training ground for Islamic terrorists. During the Cold War the United States couldn't imagine funding a war by Ukraine against Russia, because Moscow would never have let Ukrainians develop the capacity to wage war against Russia.
The superpower duopoly at the heart of the Cold War resulted from the circumstance that World War II produced two winners, the United States and the Soviet Union, each of which had a stake in preserving the postwar status quo. (Britain was on the winning side but was so weakened that its empire fell away in the two decades that followed.) The end of the Cold War transformed the duopoly into a monopoly, with only the United States to defend it. As a first approximation, the new American task was twice as hard as the one that preceded it.
Aside from a heavier burden to bear, what did the American victory in the Cold War yield for Americans? A feeling of vindication, for starters. The good guys had won and the bad guys lost. This was no small thing, although the greater benefit accrued to the peoples suddenly freed from Soviet oppression. American foreign policy has always had a strong streak of idealism, and Americans had just cause for congratulating themselves on the triumph of their ideals.
Yet freedom often comes at the expense of order. The post-Cold War world grew messy almost at once. Yugoslavia, held together by equal pressure from East and West, blew to pieces when the eastern guardrail collapsed. Terrorists trained in territories formerly policed by the Soviet Union. A post-post-Cold War regime emerged in Russia and began trying to reconstruct the old empire.
The only country at all able and inclined to arrest the slide toward anarchy was the United States. Yet it could do only so much. While arming Ukraine against Russia, Israel against Hamas, and Taiwan against China, it largely ignored military coups in Africa, human rights violations in Southeast Asia and anti-democratic backsliding in countries around the world.
To make matters worse, what actions Washington did take tended to alienate as many people as they inspired. Nobody likes a bully, and the dominant power at any time often comes across as a bully. During the Cold War, America’s reputation benefited from the existence of the Soviet Union, whose bullying was more egregious than America’s. Upon the end of the Cold War that comparative advantage disappeared. In Europe, America’s NATO allies still mostly appreciate American power, as do Pacific countries feeling threatened by China; but in the rest of the world people and governments are apt to root against America.
Why does America do it? Why do American officials proclaim the United States the indispensable nation? Why have American voters gone along?
First, it flatters American vanity and gets politicians elected. Between one candidate who says America is the greatest nation on earth and another who says America used to be but shouldn't insist on being any longer, voters patriotically prefer the former.
Second, it's good business. When Congress approves military aid for Ukraine or Israel or Taiwan, it doesn't send cash to those countries to be spent on the open arms market; the money has to be spent on American arms made by American workers employed by American companies in American cities and towns.
Third, American leaders and the American people sincerely believe that American leadership is better than the alternative. And they're not wrong, within limits. The problem is defining those limits.
Fourth, delegating responsibility to others entails accepting that they might do things differently. If the European Union, for example, offered to take over responsibility for Ukraine—Ukraine being part of Europe, after all—the EU might settle for a negotiated peace Washington didn't favor. Hegemons like having things their way, and in life it's usually the case that if you want things your way you have to do them yourself.
How long does the situation last? Until the costs exceed the perceived benefits. The costs might rise dramatically, for instance if war breaks out with China over Taiwan while the wars in Ukraine and the Middle East are still going on. At that point America will be compelled to choose. Or perceptions might change. If the war in Ukraine isn't over by next November, the expense of that conflict might help Donald Trump get elected again. And his policy will probably be very different from Joe Biden's.
Or maybe America's post-Cold War status quo persists for a long time to come. Real policemen eventually retire. Countries that act as cops don't have to.