What is power, and how much of it does America (still) have? In a time of great flux in the international system, and amid proliferating predictions of American decline, these questions have of late commanded more attention than usual. The reasons are several.

First, while many thought it self-evident that the West’s victory in the Cold War would leave America the unrivaled global power for generations, recent geopolitical trends such as the emergence of China and resurgence of Russia have called this preeminence into question. Second, the September 11, 2001 attacks and the frustrations of the counterinsurgency efforts in both Iraq and Afghanistan have led many to observe that the applicability of power depends on context; if the context changes, so does the value of prior investments in military force, intelligence methods, alliances and other traditional instruments of power. Third, the costs and tribulations of the Iraq and Afghanistan wars threw into sharp relief the relationship between reputation and power, and led to an apparent diminishing of America’s global stature. And finally, just when many observers expected to see America’s reputation improve with the election of Barack Obama, the bottom fell out of the American economy, precipitating a global economic crisis. Even as much of the world still looked to the United States to lead the way out of the crisis, the systemic vulnerabilities in the American economy that it exposed raised new doubts about economic power still being one of the pillars of American strength. So in the space of just two decades, this series of events have combined to erode a complacent consensus about American power—both about how much of it there is (not as much as we thought) and about how it is constituted (not the way we thought). That the subject is on our minds seems to be reflected in the Obama Administration’s incantations about employing “smart power”, as if the opposite were ever an option, let alone a conscious policy.

Once beyond slogans, one might consider seeking wisdom in modern academic scholarship, for a great deal has been written in recent decades about the nature and measurement of power. Whole university careers and multiyear research projects, not to mention large government contracts, have been erected on the premise that such work is meaningful. Not just American scholars but Chinese and others remain hard at work measuring and weighing away.¹ Surely, there are rich veins here to mine.

Not so fast. Recall that this and related scholarship consistently exaggerated Soviet power for more than forty years, failed to forecast the collapse of the Soviet Union and the end of the Cold War, failed to predict the scale and speed of the Coalition victory over Iraq...