Chomsky wrote that it all has to do with corporate power and oil.  Here is an excerpt from The Independent, an article entitled “The US says it is fighting for democracy – but is deaf to the cries of the Iraqis”  

Sovereignty in Iraq might well lead to a loose Shia alliance controlling most of the world’s petroleum resources and independent of the US, undermining a primary goal of US foreign policy since it became the world-dominant power after the Second World War. Worse yet, though the US can intimidate Europe, it cannot intimidate China, which blithely goes its own way, even in Saudi Arabia, the jewel in the crown – the primary reason why China is considered a leading threat. An independent energy bloc in the Gulf area is likely to link up with the China-based Asian Energy Security Grid and Shanghai Cooperation Council, with Russia (which has its own huge resources) as an integral part, and with the Central Asian states (already members), possibly India. Iran is already associated with them, and a Shia-dominated bloc in the Arab states might well go along. All of that would be a nightmare for US planners and their Western allies.

There are, then, very powerful reasons why the US and UK are likely to try in every possible way to maintain effective control over Iraq. The US is not constructing a palatial embassy, by far the largest in the world and virtually a separate city within Baghdad, and pouring money into military bases, with the intention of leaving Iraq to Iraqis. All of this is quite separate from the expectations that matters can be arranged so that US corporations profit from the vast riches of Iraq.

These topics, though high on the agenda of planners, are not within the realm of discussion, as can easily be determined. That is only to be expected. These considerations violate the fundamental doctrine that state power has noble objectives, and while it may make terrible blunders, it can have no crass motives and is not influenced by domestic concentrations of private power. Any questioning of these Higher Truths is either ignored or bitterly denounced, also for good reasons: allowing them to be discussed could undermine power and privilege.

Here is Chomsky’s practical proposal  “work to change the domestic society and culture substantially enough so that what should be done can at least become a topic for discussion.”