[Apart from the first two paragraphs, it's for subscribers only; but 'Jerome a Paris' at dailykos.com has nicely excerpted parts of the rest at http://dailykos.com/storyonly/2005/11/29/74137/607]
US global power, as presently conceived by the overwhelming majority of the US establishment, is unsustainable. To place American power on a firmer footing requires putting it on a more limited footing. Despite the lessons of Iraq, this is something that American policymakers – Democrat and Republican, civilian and military – still find extremely difficult to think about.
The basic reasons why the American empire is bust are familiar from other imperial histories. The empire can no longer raise enough taxes or soldiers, it is increasingly indebted and key vassal states are no longer reliable. In an equally classical fashion, central to what is happening is the greed and decadence of the imperial elites. Like so many of their predecessors, the US wealthy classes have gained a grip over the state that allows them to escape taxation. Mass acquiescence in this has to be bought with much smaller – but fiscally equally damaging – cuts to taxes on the middle classes.
The result is that the US is incapable of waging more wars of occupation, such as in Iraq. It can defeat other states in battle easily enough but it cannot turn them into loyal or stable allies. War therefore means simply creating more and more areas of anarchy and breeding grounds for terrorism.
It is important to note that this US weakness affects not only the ambitions of the Bush administration, but also geopolitical stances wholly shared by the Democrats. The Bush administration deserves to be savagely criticised for the timing and the conduct of the Iraq war. Future historians may, however, conclude that President Bill Clinton's strategy of the 1990s would also have made the conquest of Iraq unavoidable sooner or later; and that given the realities of Iraqi society and history, the results would not have been significantly less awful.
For that matter, can present US strategy against Iran - supported by both parties - be sustained permanently without war? Indeed, given the nature of the Middle East, may it not be that any power wishing to exercise hegemony in the region would have to go to war at regular intervals in defence of its authority or its local clients?
Furthermore, the relative decline in US economic independence means that, unlike in 1917 or 1941, really serious war risks US economic disaster. Even a limited US-Chinese clash over Taiwan would be likely to produce catastrophic economic consequences for both sides.
In theory, the desirable US response to its imperial overstretch is simple and has been advocated by some leading independent US thinkers such as Professor Stephen Walt of Harvard. It is to fall back on "offshore balancing", intended to create regional coalitions against potential aggressors and, when possible, regional consensuses in support of order and stability. Not just a direct military presence, but direct military commitments and alliances should be avoided wherever possible. When, however, one traces what this might mean in practice in various parts of the world, it becomes clear how utterly unacceptable much of this approach would be to the entire existing US political order. In the former Soviet Union, it could mean accepting a qualified form of Russian sphere of influence. In Asia, it could mean backing Japan and other countries against any Chinese aggression, but also defusing the threat of confrontation with China by encouraging the reintegration of Taiwan into the mainland. In the Middle East, it could involve separating US goals from Israeli ones and seeking detente with Iran....
it is pointless to dream of long maintaining an American empire for which most Americans will neither pay nor fight. My fear though is that, rather than as a result of carefully planned and peaceful strategy, this process may occur through disastrous defeats, in the course of which American global power will not be qualified but destroyed altogether, with potentially awful consequences for the world.