The study by a U of I college student finding 23 rationales for war with Iraq used by the administration -- all before the war -- made it's way around the blogosphere once before, but now it's in a WaPo column, so it will get far wider circulation.
The first thing to note is that the argument that WMD was the rationale for war is false.
The second thing to note is that the arguments about humanitarian intervention and about spreading democracy in the Mideast only coming out once it began to look as if WMD would not be found are also false.
Third, when this study was mentioned before, the idea that a Sept. 11 link was brought up by the press was not mentioned. But I understand this completely. The President raises Sept. 11 constantly, but as a basis for the permanent alteration of what we can accept in terms of risk -- and what that means in terms of the threshold for necessary evidence before war becomes an option, or necessary. It was then, I bet, the press who began interpreting that as an argument about Saddam ordering the planes into the Towers.
Now, all that having been said, there are different possibilities. Carol Winkler at Georgia State University has done amazing work tracking the way the justifications for Desert Storm shifted over the length of Desert Shield based on the way each justification was polling (but that work isn't available on-line.) Every White House polls, of course, and then modifies its message to an extent based on the results its getting, but this was just wild -- they were pitching and abandoning arguments wholesale. That isn't at all what this study says happened with the current White House, but until we have access to this White House's internal polls and internal speechwriter's memos, we won't be able to replicate the work Winkler has done.
We could (but who has the time) take each speech from the Sept. 12, 2002 UN speech forward and chart the justifications against, say, Gallup. It would only roughly proxy what we might guess was going on internally.
In any event, what she describes is not a wholesale use of trial balloons that are then abandoned, but a long list of arguments, used in a kalidioscope of combinations, some of which have then morphed or fallen by the wayside since the fall of Baghdad. What we really need, until we can replicate the Winkler study, is for someone to repeat this study for the time frame since the start of combat.