Pax Americana refers to a period of relative peace and stability that extended throughout the area of American influence, beginning with the end of World War II.
Pax Americana is also a play off of the ancient idea of Pax Romana, or Roman peace. Pax Romana is the name for a period of concord which extended throughout the Mediterranean world. Pax Romana began with the reign of Augustus (27 BC – 14 AD) through that of Marcus Aurelius (160 – 180 AD). During this period, the states that made up the Roman Empire did not get into any major wars. Imperial rule provided stability and basic services, as well as a degree of autonomy.
Long after the Romans, the British prided themselves on establishing a Pax Britanica throughout their empire. The British presided over a period of stability which lasted from 1815 to 1914. That period ended with the outbreak of World War I, which was followed by an era of instability which lasted until the end of World War II, when the United States filled up the power vacuum.
The concept of Pax Americana has its critics, of course. The concept has also been likened to the glorification of US imperialism. At its heart, Pax Americana relies on the idea that US hegemony is behind the long, peaceful period among North American and European states since 1945. Some analysts have argued that the Pax Americana is built on an ever-increasing cycle of militarism which has led to Cold Wars and proxy wars, among other things.
Since the end of World War II, the major powers have not been at war with each other. In the 21st century, there have been relatively few wars. However, some historians argue that there has been just as much, or even more, warlike behavior as ever before.
The political scientist John Mueller argued that:
Although states may have largely abstained from conducting wars directly between themselves, the development has not necessarily led to the demise of war or of warlike behavior in total. Indeed, states may well feel freer to engage in behavior that might once have been taken to be a potential casus belli such as tinkering in other countries’ civil wars, firing shots across bows, poaching fish from another’s domestic waters, lobbing cyber balloons, exacting punishing economic sanctions, or seizing tiny bits of territory. And civil war continues, though perhaps declining somewhat in number since the 1980s.
More broadly, Mueller argued that the Pax Americana really didn’t have much to do with America at all. In fact, he said, the peace didn’t happen because of US security activities; it happened because the developed nations were “disinclined” to fight wars with each other.
In recent years, pundits have published a series of articles claiming that the Pax Americana had ended.
In 2015, Foreign Affairs published an article claiming that Obama’s Middle East policies had brought an end to Pax Americana. A few years later, in 2019, the New York Times published an op-ed arguing that Trump’s troop drawdowns were accomplishing the same thing.