Mario Silva's Extraordinary Rendition: A Challenge to Canadian and United States Legal Obligations Under the Convention Against Torture, 39 Cal. W. Int'l L.J. 313 (2008-2009).
The issues raised in this article are quite familiar to me, because I was a Policy Analyst at the Canadian Civil Liberties Association when the story broke over Maher Arar and Canada's role in his "extraordinary rendition" by the United States to Syria. This article explains the difference between traditional extradition (also called rendition), which is a judicially-overseen process used to transfer criminal suspects from one country to another for trial, and the Bush administration's use of "extraordinary rendition" which was not overseen by a court and led to innocent people, like Arar, being deported to countries where they would face torture.
Although the U.S. and Canada are signatories to treaties prohibiting torture and sending people to countries where they will be tortured, the U.S. has always defended their conduct in the Arar case by reference to "diplomatic assurances" gained from Syria that Arar would not be harmed. When a country, like Syria, has a well-known history of torturing detainees suspected of terrorist ties, it's obviously ridiculous to accept "diplomatic assurances" as a sufficient safeguard.
Silva's article is a nice summary of the Arar case and the argument against extraordinary rendition, though it doesn't really add anything new to the controversy that hasn't been documented or argued extensively elsewhere. It's also a good example, to my mind, of how people who believe that international law will constrain powerful, determined states end up looking somewhat naive. I know it's an old criticism, but for "law" to be meaningful, it has to be backed with penalties for non-compliance. Because treaties like the Convention Against Torture, are functionally non-enforceable on a global scale, the best argument against practices like extraordinary rendition are political and moral arguments rather than legal ones.