World's Over and Underachievers

Here's an IR theory puzzle: Why do some seemingly powerful states exert relatively little influence on world politics, while other states with more modest capabilities cast a bigger shadow than one would expect? Although there is no consensus on how national power should be defined or measured, most IR scholars would probably agree that there is a substantial but not perfect correlation between national power and international influence. Indeed, one could imagine a simple regression, with "power" on the X-axis and "influence" on the Y-axis, and a diagonal line bisecting that space. I'd expect most states to array themselves pretty close to that line: as their power increased (measured in terms of GDP, population, military capability, resource endowments, etc.) one would expect to see a corresponding increase in their global influence.