The reversal of Hamdan's conviction could now affect Australian David Hicks' conviction as invalid.
The D.C. Circuit held, in Hamdan:
Because we read the Military Commissions Act not to sanction retroactive punishment for new crimes, and because material support for terrorism was not a pre-existing war crime under 10 U.S.C. § 821, Hamdan’s conviction for material support for terrorism cannot stand. We reverse the decision of the Court of Military Commission Review and direct that Hamdan’s conviction for material support for terrorism be vacated.Australia's former top military lawyer retired Air Vice Marshal Alastair Nicholson AO RFD QC in 2006, had briefed the Australian Government and had given a legal opinion that the charge against David Hicks could not be applied retrospectively. However, that opinion was ignored by the then-Howard Government. Further, the Law Council of Australia had issued this report noting:
From the outset, the position of the Australian Government was that David Hicks’ alleged conduct did not amount to an offence in Australia at the time it was committed and that it was not appropriate to introduce laws to retrospectively criminalize his actions. Nonetheless the position of the Australian Government was also that, if the allegations against David Hicks were true, he should be subject to punishment. Thus the inability to prosecute David Hicks in Australia was consistently cited as a reason for refusing to seek his repatriation. The public comments of senior government Ministers reflected the view that, if David Hicks were returned to Australia without facing trial, he would be free, not by virtue of the fact that he had committed no crime in Australia but because of a technicality or loophole which meant only that his conduct was not a crime at the relevant time.The Law Council report then went onto note:
On 8 March 2007 a written advice was provided by nine eminent lawyers [Peter Vickery QC; Professor Tim McCormack; The Hon. Alastair Nicholson AO RFD QC; Professor Hilary Charlesworth; Gavan Griffith AO QC; Professor Andrew Byrnes; Mr. Gideon Boas; Professor Stuart Kaye and Professor Don Rothwell] some with expertise in international law. In essence, that advice concluded that the offence charged against Hicks of providing material support for terrorism under section 950v(25) of the MCA was not a charge constituting a war crime contrary to Law of War. They also opined that the charge was clearly retrospective in its application to Hicks and was a “recently invented and new war crime”. The authors note that retrospective criminal laws are prohibited under Article 1 of the US Constitution. To the extent that it was claimed by the Australian Government that the MCA was some kind of “codification” of existing law, the authors also noted that there are offences under the domestic law of the US and contained in the US Criminal Code and which carry a similar description. However as they point out there are some fundamental differences including the substantial difference in the maximum penalties, the simplification of the elements of the offence, and the fact that the domestic offences were not, at all relevant times, applicable to a foreign national operating outside the territory of the United States as Hicks was.Mr Hicks waived his right to appeal his conviction pursuant to a plea agreement. However, this may be overcome by the filing of an extraordinary writ petition in the American courts.