Weapons of mass destruction, illegitimate government, oppression, slavery, genocide, civil war and border skirmishes may all be decent reasons for the US to invade another country to spread life, liberty and happiness, but those reasons alone aren't enough to get US interest. First a country must be on our radar, and to be on our radar we must have an interest, and that interest must be of sufficient economic value to justify the costs of meaningful interference.
Examples include Burma, Sierra Leone, and most of Africa, where even America's appetite for Chocolate is insufficient cause for meddling in the affairs of The Ivory Coast or becoming a media cause celebre.
Even having immediate proximity to the US has not been sufficient to move our foreign policy to more fully engage Cuba or Haiti, the latter being the most impoverished country in the western hemisphere nearly within site of hotels lining Miami Beach.
During the cold war USSR's interference in Afghanistan, Korea, Vietnam, and Cuba attracted our attention but our military response had less to do with promoting liberty and democratic values or stopping the spread of communism than our dedication to stop the spread of Russian influence. Afghanistan was slightly more interesting due to its proximity to oil and because it ferments the kinds of idiots that might disrupt our oil supply and provide a base for terrorism.
The US isn't alone in this apparent hypocrisy. The United Nations and all its member states could not have been more hypocritical than during Rwanda's 1994 genocide. Apparently, the governments of the world feel more confident rushing in after God's wake than it does man's.
So now we've invaded Iraq and many American's don't understand why. In reality they know perfectly well why but prefer denial. We're there because we're dependent on foreign oil. We're dependent on it because our lifestyles require it. We live further and further from work, enjoy the luxury and autonomy of one-car-one-person, and drive increasingly larger vehicles. Our "right" to live where we want and commute how we want is not without costs beyond $2.25/gallon. As ignorant as pretending the consequences may be it is disingenuous to drive to a No Drilling in ANWR demonstration in anything less than a bus filled with like-minded protestors or display a "No War" lawn sign with the same SUV parked in the driveway you drive 20 miles to work.
As it is, many Americans, especially in the Detroit area where I live, resist public transportation. Buses are for poor people. People who can't afford cars. Do you really think buses are filled with ecologically-minded conservationists?
Yes, Virginia, we're there for the oil.
We don't want to make states of these nations. After the oil is gone what natural resource have they left? We already have sand. We don't need religious fanaticism, sectarianism, theocracies, monarchies, etc. We have enough problems with the states we already have.