Using international law in a post-Booker world

The discussion of foreign laws and practices in Roper (basics here) has already become a subject of much blog-dialogue as evidenced here and here and here.  But today I received an interesting note from a self-described “retired Australian lawyer/law professor” who suggests that international law ought to be coming to bear in the post-Booker world.  Here are some choice selections from his amusing and insightful missive:

Re: Booker, Fanfan et al, I have been fascinated by the legal sophistry which permeates the U.S. sentencing system.  It is amazing that such a developed country could get itself into the mess that it has….

One issue that I have found most puzzling is the ex post facto/due process problem and, in particular, whether one result of Booker is that, for offences committed prior to 12 January 2005, a person may possibly receive a sentence which is higher than that which he/she would have received under the mandatory sentencing range on facts found by the jury or admitted by the defendant (the system which operated before 12 January 2005).

A question for you: Given that the US is a signatory to the Universal Declaration of Human Rights, why doesn’t article 11(2) of the Declaration prohibit the imposition of a higher penalty?  Why don’t US trial lawyers/law professors not raise this issue as a starting point? The UN Declaration of Human Rights has been referred to in well over 100 cases in U.S. courts. I have copied and bolded the relevant paragraph….

Universal Declaration of Human Rights

Article 11. (1) Everyone charged with a penal offence has the right to be presumed innocent until proved guilty according to law in a public trial at which he has had all the guarantees necessary for his defence. (2) No one shall be held guilty of any penal offence on account of any act or omission which did not constitute a penal offence, under national or international law, at the time when it was committed. Nor shall a heavier penalty be imposed than the one that was applicable at the time the penal offence was committed.

Consider also that the American Convention on Human Rights, signed by the US on 1 June 1977, similarly provides in Article 9: “A heavier penalty shall not be imposed than the one that was applicable at the time the criminal offense was committed.  If subsequent to the commission of the offense the law provides for the imposition of a lighter punishment, the guilty person shall benefit therefrom.”

I suspect that the US judicial response is that these two Declarations do not legally bind the United States Government in the sense of creating obligations enforceable in US courts, but they certainly do establish the relevant and applicable rule of international law which is part of US federal domestic law.