Referring to the split decision in Hamdan, La Rana summarizes a popular rejoinder to the "Delahunty is unethical" complaint:

[t]o further the charge that this reading of the Geneva Conventions was not done in good faith, one must contend that the four members of the highest court in the land are not just unreasonable, but unethical.

That's quite a heavy burden to carry. Fortunately, Hamdan is completely irrelevant.

Hamdan dealt, inter alia, with the applicability of the Geneva Conventions to al-Qaeda detainees held at Guantanomo. In contrast, the controversial Delahunty memo pertained to the applicability of the of the Geneva Conventions to Taliban fighters captured in Afghanistan.

Afghanistan has been a party to the Geneva Conventions since 1956.

Article 5 of the Geneva Convention relative to the Treatment of Prisoners of War says that "[s]hould any doubt arise as to whether persons, having committed a belligerent act and having fallen into the hands of the enemy, [are POWs as defined in article 4], such persons shall enjoy the protection of the present Convention until such time as their status has been determined by a competent tribunal."

The argument for nonapplicability of the Geneva Conventions depends crucially on the idea that there was NO DOUBT AT ALL regarding the protected status of Taliban fighters. This in turn requires the assumption that the Taliban was not the de facto government of Afghanistan and that Afghanistan was a failed state. The problem here is that there was SUBSTANTIAL doubt as to the status of the Taliban as de facto government of Afghanistan (this doubt is confirmed in subsequent OLC memos). As such, the full protections of Geneva III should have been accorded to all battlefield detainees until a tribunal said otherwise.

No tribunal was convened until July of 2004 in the wake of Hamdi.

To argue that the protections of the Geneva Conventions don't apply in an armed conflict between two High Contracting Parties simply by assuming away Afghanistan as a failed state so as to deny baseline human rights protections to detainees is a disgusting argument, almost certainly made in bad faith, unless he didn't bother to read the Conventions first, in which case he's incompetent. Either way, you don't have to think that John Roberts is unethical to think that Mr. Delahunty is.

[The majority of this post is cross posted in comments at Frog.]