Oppose The statement "waterboarding can be performed in ways that leave no lasting physical damage" requires a reliable medical source, which I doubt you will find, for the simple reason that it is impossible to perform any physical act of violence in a way that guarantees no physical damage. What if the victim has a weak heart, or genetic susceptibility to heart attack? An accurate statement might be "waterboarding may or may not result in lasting physical damage, or even death, depending on the severity of the attack, and victim's constitution and disposition".