For decades, South Korea has occupied an ambiguous position in the international order — too powerful to be dismissed as a small state, yet constrained by security dependence. The fracturing of American hegemony, the emergence of a more complex geopolitics and the growing assertiveness of non-Western nations have together created what may be the most significant opportunity for middle power diplomacy in a generation. The question is whether Seoul has the vision — and the domestic political will — to seize it. To understand South Korea’s opportunity, we must first understand the world it inhabits. Analysts routinely describe today’s international order as “fragmented” or “multipolar,” but both terms fall short. Fragmentation implies breakdown and multipolarity implies a simple distribution of power among a handful of great powers. Neither captures reality. As I have explained in my new book, "The Once and Future World Order" a more appropriate concept is multiplexity — a world of overlapping institutions, diverse actors and complex interdependencies, where no single