At first glance, that's obviously scary - and it seems like a blank check for the military. But at some point, we will have a global polity - I'm convinced of that as well. We've seen tribes and city states organize from bands of hunters. These far flung groups have organized into clans and then nations, and now we're starting to see national confederacies emerge. I don't think its unreasonable to assume that we will have a single, sovereign, planetary government in fifty years or so. It may not happen - but its certainly conceivable. And if it did - how would that work? Probably in a way that's very similar to how "The Pentagon's New Map" is laying it out - with international bodies like the WTO, the ICC, and the UN laying out the rules of the game and the U.S. bringing belligerents into the fold.

With that in mind I'm going to offer two quotes from a Founding Father:
In 1780: "We shall divert through our own Country a branch of commerce which the European States have thought worthy of the most important struggles and sacrifices, and in the event of peace on terms which have been contemplated by some powers we shall form to the American union a barrier against the dangerous extension of the British Province of Canada and add to the Empire of liberty an extensive and fertile Country thereby converting dangerous Enemies into valuable friends."
And lest you think that was a slip of the tongue, in 1809 the same founding father repeated: "We should then have only to include the north [Canada] in our Confederacy, which would be of course in the first war, and we should have such an empire for liberty as she has never surveyed since the creation"... this was after his excitement about the prospect of obtaining Cuba for the United States.
Who was it? None other than the libertine Thomas Jefferson! The first was in a letter to George Rogers Clark, and the second in a letter to President Madison. This sounds pretty close to Hamilton (Jefferson's political rival) who advocated taking Spanish posessions in Mexico.
It seems so counterintuitive, but now that we're really forced to deal with the idea of empire we should think hard about what it means to be an "empire of liberty" and whether that even makes sense conceptually. Certainly we didn't have an issue with it throughout hour history, but since the closing of the frontier we've pretended that empire and America are antithetical. Are they? I don't know. Our founders consistently compared us to Rome, and at some point Rome made the leap from Republic to Empire. Interestingly enough, Rome's acquisiton of territory was not what made it an "empire" in the eyes of historians - I think we should take note of this. Rome became and empire when Julius Caesar crossed the Rubicon - when he entered the captiol and took power from the Senate.
These are dangerous times and we have an obligation to use our strength for the good. But we need to think hard about what we're doing. Where is our Rubicon? Who is our Caesar? What does the "American Empire" mean. Can we polinate the world with our "rule sets" and set the stage for a lasting, unified, powerful planet - or would this very act rob us of what makes us so unique? I don't know - and I don't think these choices will be made in the near future. But make no mistake - with the Soviets gone our generation is the first in American history to be confronted with Empire - and we're going to need to think about it and deal with it. Moreover - our generation is the first in the history of the species that is confronted with a Planetary Empire. What in the world do we do with that?