You see, if it was some sort of a deliberate inside job by a corrupt government, then it's possible for a less-corrupt government to have prevented it. A plausible case for piecemeal reformism can easily be built. Just elect folks that don't consciously choose to target their own citizenry.
But if it's an emergent property that happened despite the wishes of anyone in that power structure, as a result of players acting on their own short-term greed and the desire to string the system along (such as, say, by refusing to follow up on intelligence leads because they fingered too may Saudis and worsening ties with the House of Saud might cause oil supply disruptions), then it's the whole system itself that's driving things to hell in a handbasket.
Putting more honest folks in positions of power can't fix things because the system itself constrains its leaders in ways to make them powerless to stop the inevitable from happening. Anyone political party that locked horns with the Saudis would quickly find itself the enemy of the ruling class and out of power. The public -- brainwashed into obedience and consumerism by the ruling elite -- would likewise be up in arms over no longer being able to drive their SUV's whenever and wherever they wanted.
Given this weak point in the system, it was only a matter of time until those who wished to destabilize it in the name of promoting their own ruling elite discovered the weak point and exploited it. In fact, there's even a quasi-evolutionary process at work here: terrorist groups exploiting those of their allies that can easily be brought into line by the US tend to be crushed out, while those who exploit allies who can't be brought into line tend to grow and spread.
And given the ugliness of neo-imperialism and how many people it hurts, it's inevitable that some of those hurt feel motivated to fight it. And, to reiterate, it's not possible -- absent radical change -- for the nations practicing imperialism to repudiate it. Wanting the bourgeois state to not be imperialist is like wanting water to not be wet.
It doesn't matter who's in the seats of power, what they want, or how honest they want to be. Absent radical change, the system is sure to simply produce more of the same.
[And that's all for now. More pressing things than on-line back-and-forths demand my attention.]
 And I know many of you think I'm the antichrist or something because I don't buy into such theories.