Upchurch
Papa Funkosophy
I want it to remain illegal, so the perpetrators have to take the risk of prosecution. Risk of prosecution does focus the mind somewhat, and will minimize the chance that torture will be used without careful consideration of the benefits. The perpetrators know that they will be throwing themselves upon the mercy of a prosecutor or a jury and will have to justify their actions in moral terms.
Do you realize that under your suggested system, Bush and, more likely, Cheney would be convicted of their crimes? Mercy has nothing to do with whether or not they are guilty.