I strongly believe John Howard( former PM of Australia) could be brought to justice one way or the other; there would be conclusive evidence to prove beyond reasonable doubts not only he waged an unlawful war against Iraq, but also he mislead the assembly and the public in that regard. These would constitute reasonable grounds for a successful prosecution. This could help both America and England to follow the same in bringing Gorge Bush and Tony Blair to the same fate (bringing to justice).
Professional misconduct must face the ultimate punishment (it is biblical as well); therefore, it is not up to the discretion of Australian Parliament determine his fate, if there is overwhelming evidence to justify that he misled both Parliament and the public despite the strong evidence that there were no grounds to justify a war against Iraq. You are quite welcome to look at the evidence and information put forward by SBS Date Line(Australian), etc in the past few years. What John Howard did was purely evil. He joined with US, and Briton to attack President Hussein, who was Westernize, for unscrupulous reasons. It opened the doors for the terrorists, Islamic fundamentalists backed by Iran, brutal regime such as Saudi Arabia.