Here's the official Bush legal rationale for waterboarding -- which Eric Holder recently confirmed was torture -- from that 2002 memo by Jay Bybee.

Finally, you would like to use a technique called the "waterboard." In this procedure, the individual is bound securely to an inclined bench, which is approximately four feet by seven feet. The individual's feet are generally elevated. A cloth is placed over the forehead and eyes. Water is then applied to the cloth in a controlled manner. As this is done, the cloth is lowered until it covers both the nose and mouth. Once the cloth is saturated and completely covers the mouth and nose, air flow is slightly restricted for 20 to 40 seconds due to the presence of the cloth. This causes an increase in carbon dioxide level in the individual's blood. This increase in the carbon dioxide level stimulates increased effort to breathe. This effort plus the cloth produces the perception of "suffocation and incipient panic," i.e., the perception of drowning. The individual does not breathe any water into his lungs. During those 20 to 40 seconds, water is continuously applied from a height of twelve to twenty-four inches. After this period, the cloth is lifted, and the individual is allowed to breathe unimpeded for three or four full breaths. the sensation of drowning is immediately relieved by the removal of the cloth. The procedure may then be repeated. The water is usually applied from a canteen cup or small watering can with a spout. You have orally informed us that this procedure triggers an automatic physiological sensation of drowning that the individual cannot control even though he may be aware that he is not in fact drowning. You have also orally informed us that it is likely that this procedure would not last more than twenty minutes in any one application.

As we understand it, when the waterboard is used, the subject's body responds as if the subject were drowning -- even though the subject may be well aware that he is in fact not drowning. You have informed us that this procedure does not inflict actual physical harm. Thus, although the subject may experience the fear or panic associated with the feeling of drowning, the waterboard does not inflict physical pain. as we explained in the Section 2340A Memorandum, "pain and suffering" as used in Section 2340 is best understood as a single concept, not distinct concepts of "pain" as distinguished from "suffering".... The waterboard, which inflicts no pain or actual harm whatsoever, does not, in our view, inflict "severe pain and suffering". Even if one were to parse the stature more "finely" to attempt to treat suffering as a distinct concept, the waterboard could not be said to inflict severe suffering. The waterboard is simply a controlled acute episode, lacking the connotation of a protracted period of time generally given to suffering.

Of course, thanks to today's announcement by DOJ, CIA officers can't be prosecuted for this.