Yes, torture does migrate, and there are some good examples of it both in American and French history. The basic idea here is that soldiers who get ahead torturing come back and take jobs as policemen, and private security, and they get ahead doing the same things they did in the army. And so torture comes home. Everyone knows waterboarding, but no one remembers that it was American soldiers coming back from the Philippines that introduced it to police in the early twentieth century. During the Philippine Insurgency in 1902, soldiers learned the old Spanish technique of using water tortures, and soon these same techniques appeared in police stations, especially throughout the South, as well as in military lockups during World War I. Likewise, the electrical techniques used in Vietnam appeared in the 1960s appeared in torturing African Americans on the south side of Chicago in the 1970s and 1980s, and, as I argue in the book, that wasn’t just an accident.
So torture always comes home. And the techniques of this war are likely to show up in a neighborhood near you. Likewise, the techniques that appeared in the War on Terror were already documented in INS lockups in Miami in the 1990s. There is no bright line between domestic and foreign torture; the stuff circulates.