The answer is no. Let’s start with the basic indicators. In economic terms, and even despite the current years of recession and slow growth, America’s position in the world has not changed. Its share of the world’s GDP has held remarkably steady, not only over the past decade but over the past four decades. In 1969, the United States produced roughly a quarter of the world’s economic output. Today it still produces roughly a quarter, and it remains not only the largest but also the richest economy in the world. People are rightly mesmerized by the rise of China, India, and other Asian nations whose share of the global economy has been climbing steadily, but this has so far come almost entirely at the expense of Europe and Japan, which have had a declining share of the global economy.
Optimists about China’s development predict that it will overtake the United States as the largest economy in the world sometime in the next two decades. This could mean that the United States will face an increasing challenge to its economic position in the future. But the sheer size of an economy is not by itself a good measure of overall power within the international system. If it were, then early nineteenth-century China, with what was then the world’s largest economy, would have been the predominant power instead of the prostrate victim of smaller European nations. Even if China does reach this pinnacle again—and Chinese leaders face significant obstacles to sustaining the country’s growth indefinitely—it will still remain far behind both the United States and Europe in terms of per capita GDP.
Military capacity matters, too, as early nineteenth-century China learned and Chinese leaders know today. As Yan Xuetong recently noted, “military strength underpins hegemony.” Here the United States remains unmatched. It is far and away the most powerful nation the world has ever known, and there has been no decline in America’s relative military capacity—at least not yet. Americans currently spend less than $600 billion a year on defense, more than the rest of the other great powers combined. (This figure does not include the deployment in Iraq, which is ending, or the combat forces in Afghanistan, which are likely to diminish steadily over the next couple of years.) They do so, moreover, while consuming a little less than 4 percent of GDP annually—a higher percentage than the other great powers, but in historical terms lower than the 10 percent of GDP that the United States spent on defense in the mid-1950s and the 7 percent it spent in the late 1980s. The superior expenditures underestimate America’s actual superiority in military capability. American land and air forces are equipped with the most advanced weaponry, and are the most experienced in actual combat. They would defeat any competitor in a head-to-head battle. American naval power remains predominant in every region of the world.
By these military and economic measures, at least, the United States today is not remotely like Britain circa 1900, when that empire’s relative decline began to become apparent. It is more like Britain circa 1870, when the empire was at the height of its power. It is possible to imagine a time when this might no longer be the case, but that moment has not yet arrived. (...)