Subjecting free people to military and economic occupation requires a commitment by the government and the citizens of the invading nation. They must accept the moral cost of imperialism, or the subjugation will fail.
Our government has accepted the call of empire. They have proven to be of, by, and for business interests almost to the exclusion of all other considerations. Unfortunately for the ruling elite and their corporate sponsors, somewhere around 50-70% of Americans (my guess) still harbor some notion that all people in the world are indeed equal, that they have been endowed by their creator with certain unalienable rights.
While the remaining 30-50% become increasingly bloodthirsty and frustrated over the military's inability to put down the insurrection in Iraq, the majority of Americans will (I hope) remain squeamish at the idea of outright genocide against portions of the Iraqi population (even acceptance of a war of extermination may not be enough--the Vietnamese people successfully forced U. S. withdrawal despite 3,000,000 civilian casualties).
Despite its inability to successfully conclude a war, the American government had tremendous success at starting the Iraqi conflict. It quickly became clear that Iraq had no ability to produce weapons of mass destruction and that they had no significant connection to Al Qaeda. Having lost any popularly accepted excuse for occupying Iraq, the proponents of war fell back on the claim (which worked so well in maintaining support for the Vietnam War) that we were waging a war of liberation.
This new mantra of "Freedom and Liberty" finds support in the counter-argument we hear most often in response to the charge that democracies aren't founded by invasion. The counter-argument recalls Germany and Japan both as defeated nations that formed representative governments (and, more importantly, free-market economies). Along with this reminder, we inevitably hear of the Marshall Plan, which poured 13 billion dollars into the reconstruction of Europe (after it became clear that the entire continent would elect pro-communist governments otherwise).
The essential difference between post-war reconstruction in Germany and Japan and that which has, thus far, failed to take place in Iraq stems from the original intent of the war. Despite the fairly well-proven case that the Roosevelt administration manipulated the American people into an "unnecessary" war in the early 1940s, the Second World War was certainly not a sophisticated war of empire as subsequent conflicts have been.
The Marshall Plan created a pool of capital, controlled by Germans, that provided loans to Germans to build German industry and infrastructure for the service of the German citizenry. Besides the presence of American forces, administrators, and advisors, the people of Germany understood that control of their country was returning to them (admittedly, they were occupied by a much larger force than we have in Iraq as well).
Post-war Iraq demonstrated the long distance the United States has traveled down the road to empire since 1945. The billions of dollars that might have gone to Iraqis to create and build private enterprise went, instead, into the hands of American corporations. Reconstruction, security, and transportation contracts were handed out, without proposals, bids, or alternatives, to American firms. Furthermore, the provisional administration banned restrictions on foreign possession of Iraqi resources, opening up ownership of the oilfields to the highest international bidder. Taxes on goods entering or leaving the country (including wealth) were also prohibited so that consumer goods could enter the country and displace local manufacturers with no cost to the importer. The same prohibition allows foreign businesses to liquidate and leave the country without penalty.
Not surprisingly, this didn't create the sense of liberation in the Iraqis that it did (eventually) for the Germans and Japanese. Nor has anyone, outside the United States, any illusion that America will ever again fight a war that doesn't lead directly to corporate profitability. In a uni-polar world, with no "evil empire" attempting to bring countries into its orbit, it seems we've lost all need to create strong independent nation-states.
The practicality of creating a dependent puppet state instead of a functioning democracy becomes clear when we consider the value of the resources that Iraq harbors. Trading with (actually) free Iraqi companies and individuals would be shockingly expensive compared to maintaining ownership of Iraqi mineral rights and disallowing taxation of exported resources. If we had used the same policy in 1945, we might be able to buy a Mercedes for $5,000. Of course, if we had used the same policy in 1945, we would have encountered a popular insurgency. Unless of course, we had used draconian measures to put it down.
Which returns us to the initial point: subjecting free peoples requires a commitment to empire. We, as a citizenry, have obviously not entirely made such a commitment, but our leaders have. Furthermore, they have convinced a large number of our fellow Americans to support them in their decision. If we do not wish to become subjects of the first great empire of the 21st century, we must maintain vigilance, pry our friends and neighbors off the fountains of government propaganda (on the fringes of which, "the American Empire" is already a part of the vocabulary) and resist the oppression and enslavement of foreign peoples just as we would resist it were it to happen to us at home. If we do not, we may find ourselves powerless to stop it when it does.