Niall Ferguson had a fascinating op-ed in the February 28 Los Angeles Times:
If empires are complex systems that sooner or later succumb to sudden and catastrophic malfunctions, what are the implications for the United States today? First, debating the stages of decline may be a waste of time -- it is a precipitous and unexpected fall that should most concern policymakers and citizens. Second, most imperial falls are associated with fiscal crises. Alarm bells should therefore be ringing very loudly indeed as the United States contemplates a deficit for 2010 of more than $1.5 trillion -- about 11% of GDP, the biggest since World War II.
These numbers are bad, but in the realm of political entities, the role of perception is just as crucial. In imperial crises, it is not the material underpinnings of power that really matter but expectations about future power. The fiscal numbers cited above cannot erode U.S. strength on their own, but they can work to weaken a long-assumed faith in the United States' ability to weather any crisis.
Ferguson's larger essay, from which the op-ed is adapted, is available to subscribers of Foreign Affairs here. Whether Ferguson is an American declinist is an open question. For what it's worth, I think Josef Joffe and Joel Kotkin are right and the pessimists are wrong: the evidence shows that America isn't going anywhere.
Nevertheless, perception counts for a lot. As Robert Kagan says, the idea that American power is waning motivates a lot of the Obama administration's diplomacy -- and not for the better. And the pervasive sense that our best days are behind us leads to cynicism and apathy and, above all, the decision to embrace decline. Elite loss of confidence in American institutions turns out to be a self-fulfilling prophecy. Which is why it's so important to fight it.