Two days before I left Washington in early February for my first tour inside Guantánamo's prison complex, an email arrived. "Media representatives must agree to and sign, initialing each page, Media Ground Rules," it read, "prior to being allowed access to JTF-GTMO's area of operations." Wait, I thought — hadn't I already signed media ground rules for reporting at Guantánamo? I'd been going there for the past three years and a 13-page document I had signed and turned over to military authorities at the base had covered me each time. It was an access agreement that the Pentagon had worked...