Thought : The American occupation in Iraq is not going to be like Vietnam where they were essentially losing a full scale civil war. And it won't actually be much like Israel, where the civilian populations are locked together in a white-hot terrorist / counter-terrorist battlefront.
But it might be like Northern Ireland. Where the British army went in ostensibly to protect the catholics, did some stupid and irresponsible things, and then stayed for 30 years trying to clamp down on a low intensity war between rival gangs, some of whom took the army to be the representatives of an occupying power; and where the anti-British action was occasionally brought back to the mainland.
I wonder if the Americans are prepared for that ...
Differences of course, NI is historically part of the UK, not a different country. So it was natural that the Brits would be there for the duration. The US always claims it will give Iraq back.
But the more American corporate investment there is in Iraq, the more secure they'll want to feel. Wouldn't want that Shi'ite majority voting in an Islamic government who nationalize the nice new oil production facilities now, would you? So you better make sure that you only hold elections if that isn't going to happen, or where that isn't allowed to happen. But then what are some disgruntled members of that Shi'ite majority going to do? Sabotage the facilities of course.
In that case you'll need some kind of security to protect them.
Could ask the UN to do it. But the price of support from Russia and China and France is likely to be that the spoils get shared around a bit more. And, maybe they'll be a bit pushy on the free election front too. Far safer to do it yourself.
And maybe 30 years isn't a long time in Empire.
 Britain's a different case. Remember Bernie Ecclestone? Blair is quite liable to accept a bribe for some service, do the service, then give the bribe back to demonstrate how incorruptible he is. If he has traded support for Bush in return for British corporate access to Iraq, when this starts to look embarrassing I suppose he'll simply give up any claims on behalf of British companies just to feel good about himself.