It would seem that American-style waterboarding of prisoners is not torture. American-style waterboarding of prisoners is specified by the object of pouring water into the nose and mouth of a person. This is the same object as American-style waterboarding of SERE trainees, and American-style waterboarding of SERE trainees is not considered wrong in itself, much less torture. Since they share the same object, and differ only in circumstances and intention, they must share the same objective moral quality. And since American-style waterboarding of SERE trainees is regarded as objectively moral, so must American-style waterboarding of prisoners be regarded as objectively moral. But torture is objectively immoral, as the United States Catholic Catechism for Adults says. Therefore, American-style waterboarding of prisoners cannot be regarded as torture.
I reply, a description of the object of an act is not necessarily identical to the object itself. The description may be too general, encompassing multiple acts with different specific ends, as for example "undue foretelling of the future" describes both divination by dreams and divination by demons, which are two distinct acts that are further specified by the circumstances through which the foretelling occurs. The description may also be too narrow, failing to specify any proper end or set of ends of the will; this happens, for example, if the description is excessively physical, as with "to push someone," which is only a part of multiple distinct objects such as "to help someone by pushing them" and "to injure someone by pushing them."
Thus, the fact that the objects of both American-style waterboarding of SERE trainees and American-style waterboarding of prisoners can be described as "to pour water into the nose and mouth of a person" does not demonstrate that they are the same species of moral act, nor prove that American-style waterboarding of prisoners is not torture. In particular, it seems to be an example of a too-narrow description that fails to specify one or more proper ends of the will, as waterboarding for training would seem to be an act related to fortitude and waterboarding for interrogation of prisoners an act related to justice.
UPDATED for brevity and (one hopes) general improvement.