Dhaka, April 4 -- After the Berlin Wall came down in 1989, and almost a year before the Soviet Union collapsed in late 1991, US President George H.W. Bush proclaimed a "new world order." Now, just two months into Donald Trump's second presidency, Kaja Kallas, the European Union's top diplomat, has declared that "the international order is undergoing changes of a magnitude not seen since 1945." But what is "world order," and how is it maintained or disrupted?

In everyday language, order refers to a stable arrangement of items, functions, or relations. Thus, in domestic affairs, we speak of an "orderly society" and its government. But in international affairs, there is no overarching government. With arrangements among states always subjec...