I've been watching and reading a lot about the lead-up to the Iraq War, for instance the excellent 3 part documentary "Bush's War" from PBS (up on youtube).

What seems pretty clear is Cheney and Rumsfeld reacted to 9/11 very quickly by gunning for Iraq, and they hung on to that all the way despite all of the evidence - or rather the lack of evidence - that Iraq had anything to do with it.

For me, that creates a vacuum of explanation however. What was Cheney (and the constituents who had his ear) really after, if you assume (as I think one must) that the Iraq plan was preconceived and not sincerely premised on WMD?

The interesting theory I've seen come up in searches here is the Honeypot theory. That it was a huge sponge just to soak up a bunch of terrorists on the loose, rather than allow them to strike at the US.