It is worth revisiting the TED talk by Phillip Zimbardo if only to see a few of the photos from Abu Ghraib again, to remember exactly what this country, under this administration, has done.
Phillip Zimbardo organized the Sanford Prison experiment in 1971, and the talk also contains an interesting run-through of the study, as well as a good runthrough of Stanley Millgram's electrocution study from the early '60s.
If you only have five minutes, skip to the middle of the Abu Ghraib section on the video and watch it twice. We are also linking the two seminal New Yorker features, the article by Seymour Hersh that first exposed the abuses and the photos associated with that article.
Seymour M. Hersh's "Torture at Abu Ghraib"
Photos associated with the article