Mr Howard said while tax laws were sometimes changed retrospectively to close loopholes, it was not fair to backdate criminal laws.
'It's fundamentally wrong to make a criminal law retrospective,' he told ABC Television.
I'm still looking for documentary evidence of Howard's vote on the War Crimes Amendment Bill 1987 which backdated criminal laws.
Mr Howard accused Opposition Leader Mark Latham of flip-flopping on the issue of making the laws retrospective.
Mr Howard said Mr Latham last Friday appeared to call for the laws to be made retrospective, but by Saturday had appeared to back down after concerns were expressed by Labor frontbencher Robert McClelland.
'I don't quite know where he [Mr Latham] stands on this issue but I can tell you where we stand,' Mr Howard said.
We've yet to hear of any definite flipflop, although we know Howard has previously voted in favour of retrospective criminal laws.
'And that is that those people will not be brought back to Australia, unless of course they ... tried in the United States and acquitted.'
Why is Howard taking such a different line from Britain, not only on the policy, but also on the standard of fairness to applied in the military commissions George Bush created by retrospective executive order?
Attorney-General Philip Ruddock said it would be difficult to prosecute someone successfully under a retrospective law.
'The courts have always strictly construed legislation that is retrospective in creating criminal offences and it's highly problematic whether the courts would allow your legislation to survive,' Mr Ruddock told the Nine network.
These difficulties did not trouble him in 1988 when he spoke in favour of (and presumably voted for) the War Crimes bill. Nor do they appear in Polyukovich'a case.
David Hicks' Australian lawyer Stephen Hopper accused Mr Ruddock of hypocrisy, saying his client was likely to be charged under a retrospective American law.
Mr Hopper said US President George Bush did not sign an executive order creating a military commission to try terrorist cases until after Hicks was detained.
'Mr Ruddock can't have it both ways,' Mr Hopper said.
He can't say retrospective laws are inappropriate here but it's all right for America to use retrospective laws to try these people in military commissions.'
At every stage of this process the Howard government has had to be dragged kicking and screaming towards the truth. They said the commissions were fair. Major Mori said they are not and showed in detail why. They said lawyers always attack the integrity of the court. That is untrue. They said retrospective criminal laws are always unfair. They supported retrospective war crimes laws in 1988.
The problem is not inadequate laws, it's an inadequate government that neglects the nuts and bolts of fighting terror in favour of wrapping themselves in the flag. If they'd activated the treachery sections of the Crimes Act Hicks could have been prosecuted. A second example is that after demanding the laws as a matter of urgency the government then took 7 months to list any terrorist organisations under those laws.
Lastly, it's a weird and feeble definition of fairness that finds the Bush military commissions acceptable but an ordinary trial under Australian law unacceptable and unfair.