The idea of America as an empire is currently a longstanding (within political realm) ideal which is a very hotbutton topic in the halls and parlor rooms of Washington, DC today.
The debate, if you have looked closely, is not should we be an empire, but how we should be one. The presidential debates were argued thus, along political lines. The republican camp, spearheaded by neocons, want the United States to use her force in a unilateral way; the democrats (yes, democrats want a defacto empire too) wanted to do it in a multi-lateral way, a sort of 'benign hegemon' is the way its looked at.
I diverge for a second to note that the United States is not a hegemon. Our current policy is the pursit of a hegemony, but we are not now. A hegemon is a nation which makes laws for all others which are then accept, without threat of force or co-ersion.
Most of you wish to remain an Empire, even though you do not know it. Ask yourself a simple question: do you enjoy your standard of living right now? If you answered yes, then welcome to the pro-Empire club. I do not simply refer to "low" gas prices, or electronics such as the one I am typing on- admittedly, these are organic to modern life- but the ability to eat food grown in an industrialized world; the freedom, yes, the freedom, to wear clothes, play with premanufactured goods and the like.
I am willing to fed-ex you 5 dollars if you can go around your residental abode and tell me that 51% of the products in the house are made in the United States. Current manufacturing laws set by congress state that 61% of a product must be assembled (not raw material, intial manufacturing but simple placing part A with part B together) in the United States to be considered made in USA.
Historically, down to this very minute, Empire have existed for only one reason. Economic prosperity. The three big empires that the world has seen, Roman, Britian and American, were all built upon trade. The basis of an empire is forced expansionism of one's markets. The Romans did it with swords and civilization, Britians did it with Man o' War gallies and colonies, and the United States is doing it with B-52s and the Information Age (AKA Globalization). America is the first true global Empire. Rome was regional; Britian was colonial; America is absolute.
The idea of an empire is not repression or hatred, although those tend to be intrinsically involved with an expansionist outlook, but merely that of a standpoint of 'my internal markets are oversaturated. I need to go elsewhere. Where is elsewhere?' Empires can be used for good, or for bad. It is the same as with anything in life: who is behind the metaphorical wheel designates what path the vehicle will travel.
We must first acknoweldge that we have an Empire. Once we become comfortable with this seeming stigmata- which is really not! Pax Romana, Pax Britannia... think... Pax Americana!- we can move forward and help the world.