Unlike Garton Ash, I'm not going to attempt to ascribe percentage weightings to these, except for the first which, after Alexander Downer's comments of February 11, 2003 can be confidently weighted at 0%: Australia's official reasons for going to war with Iraq have nothing to do with the welfare of the Iraqi people. US government thinking on the issue is different: there is some commitment there to the idea that a war must be followed by an effort to rebuild Iraq as a nation (link via Tim Dunlop again). This raises an interesting question: can we continue to use the liberation and democratisation of Iraq as a justification for Australian involvement in the war, when we have made it clear that we are going to be leaving this to others? Perhaps we can justify this on the basis of an international division of labour, with Australia in the international riot squad, leaving "wussy" nations (like the French and Germans) to form the international ambulance service who come in to tend to the injured once order is restored.
When it comes to motives 5 and 6, I doubt that anyone will be surprised if I say that I'm more inclined to explain the conduct of our Prime Minister in terms of number 5: This is the man who weaseled out of accusations that he misled the Australian public in the Children overboard affair on the spurious grounds that he was merely passing on the untruths that were told to him, the man who was such an ambiguous friend to Bill Heffernan - first, in effect standing aside while Heffernan defamed Justice Michael Kirby under cover of parliamentary privilege then left him hanging out to dry when Heffernan's allegations were proved baseless and most recently has found himself contradicted by none other than George Bush on the subject of Australia's pre-commitment to war in Iraq. While it is possible that on this issue he has rediscovered an ability to hold and act on moral convictions his past conduct doesn't inspire confidence on this point.
In the end, I'm unable to reach a conclusion on whether Australian involvement in a war with Iraq will have right intention: there is too much on both sides of the question to reach a definite conclusion.