Drew Vogel at Terminus has a terrific post up, "Why Abu Ghraib is Bush's fault":

...Regardless of the media response to the scandal, the fact is that Bush is involved in this up to his eyeballs. We now know that policies reviewed and approved personally by Rumsfeld and Wolfowitz concerning the treatment of POWs in Iraq and Afghanistan violated the Geneva Conventions. [And, since the Geneva Conventions were signed and ratified by the United States, that means that they also violated U.S. federal law.] We also know that White House Counsel Alberto Gonzalez sent a memo to Bush in early 2002 declaring the Geneva Conventions "obsolete" and their provisions "quaint". Regardless of the judgment of the White House's top lawyer, they remain the unambiguous law of the United States of America (something that Gonzalez probably should have mentioned to his "client")...