Julian Ku, Marty Lederman, et al. on Congress's ability to reverse Hamdan

Quick note - back when this discussion was about the Bush administration's military commissions bill, before the whole compromise discussion with Senators McCain, Warner, and Graham arose, Julian Ku (pictured) wrote at Opinio Juris, here, on the question of Congress's ability to reverse Hamdan. Marty Lederman responded very substantively in the comments. I've noted it before, but wanted to recall it now that discussion has moved on to the new "compromise" bill. If one were going to launch an attack in the courts on the compromise bill, how would one proceed? The compromise bill has a certain tension between what it says is Congress declaring to be domestic law under the War Crimes Act while also declaring that what it says is domestic law satisfies US obligations under Common Article Three. Is there sufficient tension there that it could be exploited for a legal attack on the grounds that Congress had purported to interpret Common Article Three, whereas a court is entitled to make its own interpretation of the treaty, rather than simply enacting a last in time statute? The response might be, well, the bill also says that the Geneva Conventions do not allow any private right of action; a court is merely interpreting customary international law, of which Common Article Three is also a part. Common Article Three, as part of the Geneva Conventions generally, is recognized both as treaty law and as customary international law; the United States does not dispute this. The response, presumably, is that the bill prohibits the use of foreign or international sources of law as a rule of decision; a court might respond that it is not using international sources of law in interpreting CAT qua customary international law, because customary international law is in fact part of US law. Mind, this seems to me entirely far-fetched, but I raise it because it does seem to me that the language of the bill introduces perhaps unnecessarily, from the standpoint of protecting its reception in the courts, a tension over the role of Congress's statutory enactment and interpreting Common Article Three. Or does it? I will go back and read Marty's comments to Julian's post again. (This is at section 7 of the compromise bill, btw.)